Hey xyzgra,
There may well be poker simulators out there but I wouldn't necessarily trust that they run similar to Pokerrooms RNGs (Random Number Generators). As for playing against computer players I would be concerned about what level of AI (Artificial Intelligence) the program uses.
We all generally start out as poor players because we don't know enough about the mechanics of the game and we can't identify good or bad spots.
So what do we do? We read strategy articles, watch videos, post hands for evaluation and post things we don't understand here in Beginner's Questions.
We have an awesome community here and we all started out knowing little, but with some hard work, dedication and willingness to learn it is all within reach.
Why don't you take a look at our NL Beginners Course. This will help give you the necessary tools to beat NL2.
If you have any further questions then fire away.
Regards
Laz