If you are looking for an adult I would recommend checking craigslist first. I've been seeing a lot of ads for unwanted ACFs lately so you may find some in your area too. For some reason I'm thinking that ACF are illegal to own in Florida? Anyone else heard of this? There are illegal to own in several states because they have been introduced to local waters and have wreaked havoc on wildlife. Not sure if this is the case in Florida.
It just might be something to consider if you are going to have a frog shipped to you.
Anyway, I've purchased adult frogs from xenopus express. Xenopus Express Products - Xenopus Suppliers
Shipping is expensive, that's the only draw back. The frogs I ordered, a piebald and two retics, were very beautiful and healthy.
As for keeping two females in a tank together, it is absolutely fine so long as they have enough space. Anything smaller than a 20 long would be cramped.
Whatever you decide, just make sure to quarantine the new frog for a month. You wouldn't want to pass any hidden illnesses on to Olive.