I agree with above comments on saving your money for a better bike.

Speaking of riding, you did not say what type of riding you would like to do. You have a MTB/trail bike there, but you have set it up with slicks and you were talking about getting a rigid fork and 700c tires. If you are doing mostly distance road riding then you should start keeping your eye out for road bikes. If trail riding (light offroad) is more your thing then something similar to what you have now will do (better frame and components though). Alot of bicyclist keep a stable of bikes for the type of riding they plan on doing. I know that is typically too expensive to do in motorcycles but think of it as street, cross, enduro, track, etc.

You still have a working bike that looks in decent shape. That should give you time to look. You might even see a bump in used bikes when the cold weather comes in a few months.

There probably is not anything worth saving on your bike. If you do get a new bike, you would be better off selling or donating yours.

Good Luck.