What are you looking for like cheap upgrades.Well for starters,like you said u need new suspension but u are on a budget,go get some kybgr2 struts all around are like 135$ for them all and get your self a set of 16v springs (i have some ill give ya for free)they are a A++++++ upgrade.
You are looking for performance,do a tune up to her like plugs,wires,cap&rotor,fuel filter,oil change,k&n drop in filter.
You said u wanna make it a autocrosser,most local junk yard always have a gti there or a gli jetta or some sort with rear disc setup i highly suggest that.(not sure if yours does already have it or not)
You can get your self a nice cam and camgear setup up used for about a $100 or get them brang new for like $200.Check up top of the webpage and click on
http://www.euronationmotorsport.com/
Point being you can make your car fun,daily driven,sporty CHEAP!!!
good luck any question get back to me