It looks like the poor frog was bloated when you bought her, probably from bad water conditions in the store. However, I believe there are some circumstances in which bloat can be contagious. Your remaining frog looks okay, but I would isolate it from other aquatic life for a week or two.

I would do a 25% water change on the new frog weekly, perhaps more if you aren't using a filter. It should be in at least 1 gallon temporarily and then a bit larger for a permanent home. Since you only have the one remaining frog you might as well set it up in the tank you were going to use. Just make sure to thoroughly clean it first (no soap of course).

I'm sorry that your first venture with clawed frogs didn't work out too well. Best of luck with the remaining frog and it's future friend(s).