where to buy a new engine?

[NoHachi]

Thats no problem alimonos. Just realise that the chance of enginefailure is very big when you don't know what you're tinkering with. Basically turbo's are made up from the following parts:
Airflow construction, fueling solution, ignition solution, engine modifications.
These factors can be combined in various ways and for different $$. The most basic setup is:
Airflow: turbo manifold(log-type), cheap junkyard turbo (eg.saab), piping from compressor outlet to throttlebody.
Fueling solution: std computer inc rising rate fuel pressure unit.
Timing solution: back off the base timing a little bit.
Engine stuff: none
That should get you a safe 4-6psi anyday. Depends a little bit on the condition off the engine etc. That would equal about 4/14.6=27% to 6/14.6=41% extra power.
Once you have that basic setup you can start and improve it in steps. The first logical step is the addition of an intercooler in the inlet stream. The cooler charge will allow you to run 6psi safely with a bit more timing (big improvement in bottom end power). You could maybe squeeze out 7 or so psi with conservative timing (less ideal overall power, but more on top).
After that its time to get creative with the rest of the factors, but that tends to get complicated and expensive quite soon.