The stock coolers are a bad joke. The Arctic Silver thermal compound will help you, but it can only do so much. If I were you I'd get an aftermarket cooler on your 4770K. The chip will need it as it runs hotter by design.
As for plugins, case fans should plug into SYSFAN headers, and CPU fans are coupled with CPUFAN headers. Both located in various spots on the motherboard. There are usually between 1 and 2 CPUFAN headers, and 3-4 SYSFAN headers.