Unfortunately, your timing belt replacement isn't a quick, easy or cheap repair. You could actually have some serious engine damage depending on where in the engine stroke the pistons and valves were when it did snap. It's about 50/50 whether you'll just be able to just replace the belt or end up needing a top end rebuild on your engine. A timing belt replacement is a little labor intensive so I'd expect anywhere from $300-500, maybe a little more depending on where you go. If the pistons hit the valves, you could be looking at $1-2K+

I'll keep my fingers crossed for you that a belt replacement is all you'll need. Good luck.