Macbook keyboard damaged after coffee spill

Hi,

I spilled coffee on my macbook about a month ago and put it into a bag of rice for a week to try and get the moisture out.. but it had been turned on for a while after it was spilled, so had already done some damage. Basically, the hard drive seems to be completely in tact: all of my files are still there, unharmed, and the screen works perfectly.

Only a few of the keys on the keyboard, however, work... basically just the top row, space bar, and enter keys. Also, the mouse pad stll works to move your finger around on, but every time i click with it it acts as if the CONTROL key is being pressed down, and therefore uses a "right-click" function rather than a normal click! this is ok for opening some things, but bviousy still very frustrating!

I sm a broke student and am trying to work out how to fix this with the least money possible.. have seen online that you can buy an entire top case for the mac and replace that (my house mates are fairly computer savvy and would be able to d that for me)... but how do i know if this will fix it? could it be something with the logic board instead?

I know that I can buy a portable keyboard and mouse for the laptop, but am hoping to fix it instead... if i can.

Any help would be greatly appreciated, and any suggestions welcome.

Thanks.