before you go spending massive dollars on making it go fast, set yourself a plan so that after you blow this $1500 (tax im guessing) then you will want to save more and do the next thing. If its not a long term project, dont waste your time.
Second, dont go spending it on the car if its not gonna add any value unless it needs to be fixed to keep its current value. Things like
1. a good set of wheels\rubber combo if bought through trading post will increase value without blowing budget ($5-600)
2. Lowering car - Second hand springs and new shocks ($4-500)
3. Panel filter ($1-120) and CAI (cold air intake - cost me nothing for pipes from my work but $20 from bunnings plumbing section)
4. Set of turbo calipers and discs - not sure of price but you'd be looking around $3-400 im guessing.
Now you have a reliable car that can handle like a dream and will stop when you build a motor or slap a turbo on.
Just be mindful at all times about insurance becoming void if you lower it too much or increase wheels track by more than 1" (distance from centre of one tyre to other centre)