Koyo, NSK and GMB are well known brand names. Have used these types of kits off of Ebay with good results (although no experience with these particular kits).
For discount aftermarket parts and a selection of timing belt kits also try
www.rockauto.com.
Suggest picking up a new spring at the Toyota dealer (under $2).
Since you will have access if you have the time and skills might replace the cam, crank and oil pump seals.
Pickup up some kind of service manual on this engine before starting the job. Not too difficult but a lot of tight spaces and you want to make sure you reinstall the belt correctly.