I looked at some of your games and I think middle 1700 is definitely a reasonable goal.
From the game you sent I learned that you have good calculation abilities, and you are alert to your opponents threats. On the other hand in the game you had a lack in development,and as a result your control over the centre was minimal. at move six you played-
6.Bc4 problem is it runs in to 7.Nxe4,dxe4 8.Qh5+,g5 9.Qxc5 with a winning position for white. therefore for black you should have played 6.Nh6 preventing your opponents threat Nf7 and preparing to develop your bishop and castle.
7.Qf6 is a nice move though your rook is still trapped after white plays either be3 or Qe2 preventing your mate threat.
10.Nc6 is ok but you have a better move. instead 10.Bb4 is strong. your opponent cant play 11.Nc3,Bxc3 12.bxc3,Qxc3 13.Qd2,Qxa1. therefore your opponent is forced to play Nd2. This causes your opponent some issues because he cant develop his pieces. (this is why the theory for white last move is c3 not c4). now if you will try to think of moves for your opponent you will see he cant develop. Your bishop pins the knight and can never be chased away, because a3, Ba5, b4 runs in to Qxa1. This causes the continuation to be- 10.Bb4 11.Nd2,Nc6 12.g3 (only developing move for white) Nd4 13.Qd1,Nf3+. and you are doing really well.
15.Nf5 is a mistake after 16.Bc4 you are loosing material.
Better is 15.ne6 now- 16.bc4 you play Bb4+ 17.Ke1,Rd6 and you don't loose material (Bb4 is forced because if not 16.Bc4,Rd6 17.Bxc5 wins for white).
17.Kb8 awesome move Nxe3 threatened ;)
19.Rd2 caused you to capture whites rook by a forced combination, but you gave a knight and a bishop for it so you didn't gain material but you showed good calculating abilities :)
If you would have played rd8 whites knight is NOT trapped but after 19.Rd8 20.Nf7(forced, if not you play Nh6 next and trap the knight)Rf8 you get a knight and bishop for your rook.
23.c5 amazing move! the next few moves are forced. you gain a bishop for your past pawn. the reason your opponent cant play Be6 (and save his bishop) is you play next Qc2 and Rd1 winning whites queen!