Doing it on your own (assuming that you've done something similar before) will take you 2-4 hrs.
Read the Haynes manual (very good on this), study & understand each step in advance. Also, there was a detailed post here about it recently.
Check the condition of the tensioner and idler pulleys, usually it's a good idea to replace them as a set. Chances are that your belt snapped because either the tensioner or one of the pulleys failed.
You'll need to fabricate the camshaft holding tool (that flat piece of metal) mentioned in the book to get the engine back to sync.
Doing the water pump will add a good amount of pain and labor to the project, I'd do it only if it's necessary.
The belt costs cca $40 (or $100-120 for a kit with the pulleys), the valve cover gasket is $20, all USD.
Tiv
