Hello and welcome! Your piggie is adorable and if you have trouble finding Coro than you can always use a shower curtain but you have to use fleece for it. Here's my cage:
New (bigger) cage - Guinea Pig Cage Photos
And that blue thing is there old cage!
Remember, as hard as it is, NEVER buy an animals from a petstore. It's worse than buying from a breeder. I know how hard it is to want to take a pig out of a bad situation but you will just be continuing a huge horrible cycle. When you buy one pig, it will be replaced by 4 more. Another pig will be bred (probably back to back and in horrid contions) and it will happen again.