As much as I hate to say it... Do you have a Livebearer Breeder Trap? If so, he'll be OK in that till you get the 10 gallon. Or at least better than he is now.
How big are the Cichlids again? And what types of Cichlids are they? Like I said, I had my betta in with an Angelfish and a Breeding Pair of Kribensis for a good 2-3 weeks so he should be OK till you can get the 10 gallon either today or tomorrow.
It is probably not a good idea to put him in there now anyway. I just found out today that one of my Jellybean Parrot Fish has ich. He is by himself in a plastic bowl (It is the best we can do now). If we do put the betta in, we could risk him getting sick too. I don't know what to do.
Good, you're going to have to go through a Fish-In Cycle. I would not suggest taking any media from your other filter since your other fish are ill. Take a look here to read about Fish-In Cycling. http/www.fishforums.net/index.php?/topic/224306-fish-in-cycling/