I noticed that in this thread here:
http://tugbbs.com/forums/showthread.php?t=205006
you posted that you bought at Vallarta Gardens in February. Since it's been only seven months, has that been enough time for you to completely pay it off? If you haven't paid it off, then you will have one heck of a time trying to find someone to take it even for free.
My best suggestion right now is to pay off the "mortgage" if you have not already done so and then try Denise's suggestion of using TUG's giveaway section.
Also, if you have not paid off your mortgage, do not go looking for these companies that claim they can "cancel your mortgage", "end your timeshare agreement", etc.
The other suggestion is what many have done here on TUG. Contact VG's customer service and say that you will post many negative things about them and your experience with them on TUG, ripoffreport, Red Week, etc. Many times these Mexican TS companies will work with people to rescind the contract provided the buyer removes his/her posts and declares that the issue has been solved satisfactorily.