Hello!
Well I will try and help you out here, but I am sure there are many others out there that will chime in as well.
If you have either Microsoft Flight Simulator 2004 or X (latest version for now), I would recommend looking into the Level-D 767 from LevelD Simulations.
It is a nifty aircraft with a fully functional FMC which is sperate from the standard GPS used in the MSFS series. I however cannot vouch on how realistic it is from the real 767 FMS as I have never flown one.
The add-on has been around for a while now but the price hasn't gone down at all. Last I checked it was still around $55 for the add-on.
Here are also some links that might help.
SmartCockpit - Boeing 767
Mike Ray has a pretty cool book for the 757/767 checkride.
Amazon.com: Boeing 757/767 Simulator Checkride Procedures Manual (9780936283029): Mike Ray: Books
Hopefully this information can help you out with the sim.
Good Luck!