I need a diagram for wiring a GFIC cercuit with a 25A GFIC breaker at the box.

This will save me a whole lot of typing. How To & Help - Installing a GFCI, how to install a GFCI What are you powering with 25 amps, you must use #10 wire.

Also try the instructions that come with the GFI breaker.

Here is for a GE breaker, for example:
http://www.geindustrial.com/publibrary/checkout/Installation%20and%20Instruction%7CGEH-3476%7Cgeneric