Housing Comet Goldfish

Recently, I rescued two comet goldfish from a friend who was keeping them in a small, filthy bowl. I had a cycled ten gallon tank already set up, so I put the two in there for the time being. My question is, will they be okay for about a month until I can get them a larger tank? And is 75 gallons enough or do I need to go up to 100? I feel bad for keeping them in such a small space, but I thought that was at least better than their small former home.