Don't mean to be rude Greg - but seriously suggest you take the bike to a shop and / or watch someone else do this first before tackling it yourself. The tire is probably the right size, you're just not familiar with sizing conventions and the basics of changing a tire and tube.

A repair will run you about $15. Believe me - you can inadvertently do a lot more damage than that trying to tackle things yourself if you don't know what you're doing. Scrapped rims, pinched tubes and stripped axle bolts are just a few. Everything is easy when you know how - but for every right way to do something there's usually multiple ways to screw things up.