Knowing that white is rated at approx 1400 and black at approx 1300 could white have been able to pull a win from this position.

Thank you for your help.

Accepting the draw was IMO a mistake and would have been a big mistake if he were the lower rated player. At least you didn't lose rating. Rook and pawn endings are VERY tricky. Sure they're usually drawish given perfect play... but higher rated players than you and your opponent make big mistakes in the ending. I honestly think the both of you looked at that ending, didn't quite know how to proceed, and copped out.  You had an advantage. You should have played on. I would absolutely question the ability of anyone rated below FIDE expert to be able to look at that position and call it with any certainty a draw or not. 

I'd love to play black here.

well i think black is the only one playing for a win, so the answer to your question is imo 'no'.  Unfortunately i dont see how black can make any progress either, but vs a 1400, who knows.  I think i'd have played on for a bit, maybe putting my rook on g5 via d8 and g8.  Probably still drawn, but gives a low rated player a chance to blunder.  If it's a blunder in itself, then I would be reasonably confident I would get away with it, assuming they are chess.com ratings and not otb.  

They are online chess ratings.  I have played him many times and he has beat me most of the time.  I do tend to blunder in the ends so I accepted the draw.  Maybe at higher levels Black could have won, but I don't think I would have been able to come out on top.

Thank you all for your input.

To me it seems it's a draw.(I'm not sure though)

After 1...a4+ if white goes to 2.Kb4 I would play 2...Ra6 forcing him to reatreat to a3 as 3.Kxb5 is met by the simple 3.Ra8 where black has to reatreat his rook to stop the a pawn and then black could have grabbed the h5 pawn making an outside passed pawn, and 3.Rxd5?? is met by 3...a3 winning the game. After 3.Ka3 Rc6 4.Rxd5?? is met  by 4...Rxc3+ 5.Ka2(Kb2 or Kb4 are met by Rb3+) 5...b4 and I think black can win this endgame. If 4.Kb4 a3 then 5.Kxb5 is met by 5...a2 6.Re1 Rxc3 7. Kb4 Rc2 8.Kb3 Rg2 9.Ra1 Kf5 10.Kb4 (10.Rxa2?? is a clear win  for black) 10...Ke4 11.Kc5 Rb2! 0-1. 5.Kxa3 Rxc3+ 6.Kxb4?? is met by 6...Rf4+ winning the d4 pawn and the game but after 6.Kb2! the game is a draw I think as the d5 pawn will fall.

I did the analysis on  my own so there might be some mistakes.

Update: A quick computer analysis gives this as drawn (the initial evaluation gives black an edge...but it dissipates) -- a few of the variations go pretty deep. (+20 moves) There's room for error to be sure, but you can rest easy knowing that you didn't give anything away. I still think you should have played on a bit if only for psychological reasons: don't let him know you're eager for a draw!  He should have the feeling you want his head in a basket.  

 Sure.