Use DFU mode to restore, there are several easy to follow guides, on Windows I go by the device connect/disconnect sound, but the easiest way seems to be as follows:
1. Hold power for 5 seconds
2. Hold start holding home for 10 seconds (DO NOT LET GO OF POWER)
3. Let go of power and continue holding home until iTunes recognizes it (most guides say for 30 seconds but it usually works after 15 for me, if it doesnt you messed up, try again, it usually takes several tries.)
iTunes should restore however you will lose your unlock and jailbreak so be prepared to redo that. Btw why are you wanting to restore, from your post it appears to be working, just not recognized by iTunes, in which case it is probly an issue on the Mac, if possible try a different one or as a last ditch use Windows and use the device connect sound trick to restore or see if its just your box.
EDIT: If it works please hit thanks
