Search Results: saying i love you too soon

Hello girls (wave).
I am in a dilemma about whether I should stay with my girlfriend or not. My feelings are a little complicated, so here's my attempt to put them down in straightforward text:

I have been with my girlfriend for exactly 2 years now.
I strive for the best, in everything I do and affiliate myself with, and it even reaches towards my partner too.

So my current GF is a lovely person. Honestly the sweetest girl ever. She's very loving, caring and giving.
Like me, she too is a monogamist, so that is something we both like about each other.
However, here is where the problem comes: truth be told, she's a little numpty (put extremely gently), and at times, very immature.
Throughout the course of our relationship, I've tried all sorts of ways to change her for the better. In fact, I find that we both have a mutual impact on the way we perceive life: I've become a much nicer person, and she's sort of become a little more cynical (trust me it was needed).

Anyway, the thing is, I am consciously taking steps to improve myself and my behaviour, I'm not saying I'm perfect but I strive for perfection, and she's isn't - Ok, maybe to a bare minimum - she shows that she wants to be better for herself and for me, but its genuinely next to no improvement at all over the 24 months we've been together now.

So Im at a crossroad: what do I do?
The poll sort of summarises it, but feel encouraged to tell me how to handle things?

Although its quite idealistic, and perhaps life just doesn't think I deserve it yet (although I beg to differ); my ideal girl would be smart, easy going, confident, mature, classy and monogomistic. Looks are important too, to me, for more than the obvious reason (I'm not shallow).

My current GF simply put loves me a lot, is a monogamist, but isn't any of the other things I look for, yet, and doesn't show any signs of achieving them any time soon - if at all.
I don't want to change her too much, but yeah:
Recommendations?