Could i have won

This was a game i played recently against a higher rated opponent. I felt i didn't do too badly until i lost a rook at the end. I just wanted to know if there were better options in the endgame which could have drawn or even won. (Towards the end i was aiming for a stalemate which my opponent would have walked into by promoting)

42...Rh2+ - Ok, so you missed it. The important thing to understand is that at that point in the game the position was already beyond lost. So blaming it on a single move which lost faster is not really important. What you need to figure out is if you realize why the position is lost before that. Once you do, you would have learned the lesson from this game.

You most definitely should have resigned. The position is not even slightly difficult to win for black, and playing in the hopes of a stalemate blunder shows a lack of respect for the opponent. It is also something that strong players never do.

It's not a coincidence: that habit (not resigning when completely and utterly lost) prevents you from improving, because you train yourself to still have hopes (in your mind) of saving such positions. If you stop that, and learn to let go (even if there is the odd 1/1000 chance of something odd happening) and train yourself to treat these positions as lost, you will be much more cautious in your play. 

I think that one thing that players until about ~1400 (sometimes even a bit beyond that) lack is the understanding that the majority of games end a very long time before the end is really visible (and knowing to recognize these lost/won positions). 

Your comment on move 39... Rxb5 - 3 pawns down - lets try for a draw, shows this very clearly: 3 pawns down is already way too late to look for draws. There is no way youl'd find a way to save the game at that point.

Actually, most of the time, even 2 pawns down is already way to late for that.  (in many positions, even one pawn down is too late, but at least here the exceptions are not that rare).

On a different note, your game is dominated by hopes, rather than by thoughts.

Don't hope your opponent makes a mistake. Your comments show you think that is a valid method to use all the time (such as "You never know, if he takes I win..."). What you should be doing (if you want to play better Chess), is ask yourself, "IF the opponent responds well to my threat, do I like what I've done to my position". If the answer is "yes", play it, if the answer is "no", don't play it. That simple.

22.Qd3 - You say that you could have taken on d6 and "evened things up" - no, surprisingly, the position is already lost for white. The king position along with black's passed d pawn, annoying temporary pin on the f3 knight and vulnerable e4 pawn mean that white is already doomed. Too many problems to solve.

Now, in this instance,  you forgot that you played Qd3 to protect the e4 paw too... Bxd6 instead Qxe4+ and black reaches a win VERY fast (Qe2 allows Qxb1 and anything else Bxf3. It's over.

But I've looked at the position, and I don't think there are ANY moves that save white, so it doesn't really matter. 

 I wonder. When do you think the position became lost?

6.g3 - Indeed, a very strange move, as it weakens all the light squares on the queenside. It is often played, but usually when the bishop goes to g2 instead of to the queenside, so that it covers those light square weaknesses.

Black missed a chance to reach a winning position with Bxf3 (after Bg2 Rg1) followed by Qa4, but other than that, I'd say that the minute you turned the position into a lost one was d4??

Numerous mistakes by both sides were made in the following few moves, but that was the point at which the position turned from strange (difficult for white in my opinion), to what should be an objectively lost position.

Now, look at d4 again. Your king is stuck in the center of the board, the LAST thing you should be thinking about is opening the position. If black would have played even slightly better than he did at that point, it would have ended then and there. But he played well enough to maintain an advantage (he lost the completely winning position a few times and got just a position which is vastly in black's favour... but d4 was defeinitely a very bad move. Interestingly that you did not even mention it as a possible source of problem.

 So your saying that being two pawns down is pretty much a loss, that surprises me. Against a better player, yes it probably would lose, but im certainly not going to throw in the towel just for going two pawns down. If i started playing like that i'd have to steer well clear of gambits. It just seems rather lame to me to give up after losing two pawns.

 Still i accept the advice about resigning early.

 No I'm saying that you need some compensation (even if clearly insufficient compensation) to have reasonable hopes, and that in the positions I mentioned in the game white was both material down AND with the more exposed and inferior position. The game probably cannot be saved at that point.

I was trying to just let the original poster know that the position was already very bad (and probably lost) long before he seems to be aware of it. When to resign is a different issue, but even then, being two pawns down and funnily enough, your oppoent seems to be the one who has the "compensation" (he has more activity as if he is the one who sacrificed... ), it is a good time to start thinking about resignation, and in any case, the correct time to start thinking about drawing is before that. 

When you lose material with no compensation, thinking about how to draw the position is a good idea. Playing for more until you are already two pawns down (still, without compensation... It's different if you can sac a second pawn and get some compensation) and only then start thiking about a draw is a sure way to lose many games.