Rebuilt my 7.25 rear end and bad news....

My ring and pinion are worn to crap. They will still work for a while. but there is a noise going on back there that i don't like and neither do my girlfriends.

So, i'm looking to replace it as fast as possible. Where do y'all buy these type of parts? Ideally, I'd like to buy a replacement made in a first world country, preferably the US.

Additionally, i had to fanagle some parts together to shim it up to spec. Anyone have a good source for spacer shims for this rear end?

Thanks for any help, i can't take this whiny rear end.