well i checked out op's car today. seems he is running an ebay t3/t4 turbo which is on its way out. has a bit of shaft play. so i kinda talked him into going with a smaller turbo. but first he is going to need some programming. the injectors are stock so i told hime not to drive it very hard. he has a pretty decent base to start with, but with a more apropriate sized turbo with some injectors and tuning he should be pretty set.

also op, i completely disregarded the fact that you engine is still on stock rods. this is your biggest limiting factor as far as making power goes, but you said youd be happy in the 250 to 300 range with decent spool, so the stock rods may work, but you for reliability's sake, you may want to look into getting some forged rods in your engine.

i looked on vortex for like two seconds and came up with this, which would be a much better option than what you have. the 50 trim is a very common upgrade
VWVortex.com - FS:Garrett 50 trim .63 ar

add the 440cc file from unitronic (you can find it cheaper used)
Audi A4 B5 1.8L R4 / 5VT (Turbo) ECU Tuning Software - by Unitronic or i found this, but youd have to have it coded for an auto trans VWVortex.com - GIAC 440cc DBW File Software & ECU for GT2871R e, GTRS , T28, GT2860 Turbos that listing is a bit old, but you could still try. all that with some 440cc injectors and youd be set