What a crappy situation to find yourself in. I am so sorry. Thank you for taking the kittens in and looking after them.
Most definitely keep them separated from your other cats. At least until you can get them retested.
A site for you to check out. Maybe it will help.
http://en.wikipedia.org/wiki/Feline_leukemia_virus
Also, I have sent a PM to Dr. Lee. Maybe he can give you some more info.