Alright, assuming that you don't know much more than how to pump gas you're going to be in for a real and rude awakening.
Working on cars can be complicated, but it isn't impossible.
If you're willing to have your car torn down for a length of time while you try to figure out how to change the engine out, then find a buddy who does know something about cars and enjoy. But don't expect a quick turnaround, and DO expect to learn a hell of a lot more than how to pump gas.
If you don't know jack about cars, and don't want your car torn down for a long time then be prepared to spend a small fortune paying someone else to do the work for you.
If this second scenario is more you then spend some time asking around and talking to people and try to find someone to do the work for you that is reasonably priced. But more important find someone that you can trust. Otherwise you could get taken to the cleaners and end up paying for a lot of hi-tech sounding stuff that really won't help your performance, but will help your mechanic build a new addition to his house.
The final option - assuming your engine isn't totally junked out and worn down - is to look into making small modifications to your car to help performance a little here and there.
Just so people don't accuse me of trying to convince you to turn your car into a ricer - just remember stickers, neon, and wings are not performance parts.
Going the minor mod route will let you spend money slowly while you keep your car up and running, and it will give you a chance to get your knuckles dirty while deciding if you're really up to the task of doing a major overhaul. This option will not turn your car into the road burning hot-rod of your dreams, but if you do the work yourself you'll still be proud of yourself and the improvements. Then you can decide what route to follow.