Well first off, you don't want to rush into a build head first and try to do everything all at once.
Start with the basics, you want your car to "breathe" better. Get a full exhaust and intake system.
Example build list:
-DC Header ($100-$200)
-2 1/2 inch header back exhaust ($200 or so depending on shop)
-AEM Cold air intake ($150-$200)
That will give you a few extra ponies and improve gas mileage a little bit while at the same time giving your car a nice sound.
If you want to step it up a little more look into an aftermarket intake manifold and throttle body. Skunk2 makes some pretty decent stuff.
-Skunk2 Intake Manifold ($300 or so)
-Skunk2 66mm Throttle Body ($200-$300)
After you get those basic mods out of the way, then you can start looking into the actual motor build.
Remember, take your time and do the build in stages that way you can keep some money in the bank
in case shit happens, you don't want to be caught living from pay check to pay check and then scrounging
through your piggy bank for coins to pay for gas. Be smart and have a cash cushion in the bank, no matter
how much money you make.
For a motor build you're going to want to look into High Compression pistons, rods, valves, springs, etc.
Motor builds can get quite expensive and make sure you find a good reputable shop.
I recommend staying away from Ebay brand parts because they tend to be poorly manufactured and have
high failure rates. The last thing you need is a part to break and destroy your motor.