A lot depends on the circumstances. If the belt snapped at low rpm and you engaged the clutch in time then yes a new belt will all you need (personally I'd swap the tensioner as well).
If you rolled the car at any kind of speed with only the bottom half of the engine rotating there's a chance you may have popped the head gasket due to compression being out of sequence. I did this to my Fantasia when the belt went at sixty. So instead of a ten minute job replacing the timing belt (and tensioner) it'll be an hour to replace the head gasket as well.
Plenty of guides here to do the job yourself and if you get stuck we're here to help.