Parts cars are EVERYWHERE! Like Silver said.............If you want it done right, do everything while the motor's out.

Water Pump
Thermostat
Check/Replace Timing Belt
Misc Gaskets
Int/Exh Gaskets
Various Hoses

Everything else bolt on is usually available aftermarket I.E. Radiator, Intercooler piping, etc...

Things like TPS's and CPS's are usually widely available anywhere.