didn't see thsi post till now.....
few things you gotta look for...and since you got the GTS, its has a built in voltmeter...
A) is the volt meter atleast above 13Volt....cuz the starter won't turn fast enuff if its less then 12.8volt.....if its less, there's a possibility that one of your cell is dead.
B) if it makes a clicking sound but doesn't turn the engine, your electric motor on the starter is not working (cuz of brushes etc etc) but since you can hear the clicking sound, the solenoid is ok.
C) whats the CCA (Cold Cranking Amp) on the battery??? anything above 550CCA is enuff for 4AGE. (usually need only 180 to 220 or so) so dun really matter but its nice to know it
D) yours is a manual....put it into 2nd gear and push start it!...if it starts, its possible that its your battery or the starter.....if it doesn't start.....ignition, electrical prob, etc etc etc....
if it starts but then it dies rite after, your alternator is gone....
well....few basic things here that may help you....but you probably already took it to the shop :p