You can always start off where you left off in any Game of the Month thread : D
It wouldn't be fair to force you to start over, right?
About the Skyward Swords vs Halo, it really depends on what you like more. Do you have friends who play Halo Reach? If so, then I would say forget about SS and get Reach. If you don't have any friends or not that many who play Reach, then get SS. That's just the way I think of it though. x)