If you want to get it running again, just put on the turbo, but there could be a bit of fabrication to make the t3/t4 fit. That alone is not an upgrade, but it will make your car drivable.
If you want to improve the performance of the turbo engine, do some research. This site is an amazing resource, so decide what performance level you want, then figure out how to meet those goals within your technical capabilities and your budget. Good luck, it's a lot of fun.