I couldn't find specs online anywhere for that bike (past 700C) so I am not sure what size tires it will take. It looks like it is a Carbon Fiber bike which means it is probably more race oriented and it might not have the space to go with a fatter tire. Also it looks like it is not set up to take fenders easily which is a good thing for a commuting bike to have.
I would say ask the store associate but WalMart does not have the most knswledgable people. There are lots of great options in the used market via Craigslist if you know what to look for.