TBH, £1250 is an astonishing price. Well played tbh.
I'd love to have a project car like this and do as much as i could to return it to it's former glory (get rid of those **** alloys for a start). I'm guessing you could replace all the broken stuff in it for £100, make sure there is no underlying problems, give it a good polishing and wax, then turn it around for £2000+ (assuming it has the usual FSH/MOT etc).
If you're handy with a spanner, there really isn't that much that is going to cost your a fortune on a 330i. Apart from tyres but, ahem, i see you've got around that issue.
Bushes are a major problem with the 330i, so give them a check over. Rear shocks will set you back about £90 for a pair if you need them for Sachs OEM ones, about £150 for fronts. Springs cost £30 for a pair of rears. Bottom line is, if the engine is ok, the rest you can tidy up yourself with extensive use of eBay and ECP (with 30% discount).