Find a container, plop in some plants if you can, make sure it's properly heated, feed them accordingly. Do water changes to make sure the water is clean, after two weeks or so they should be safe.
Also lovely rehome for the goldfish. :) Good job on finding them such a beautiful nice home.
Ah, cool. Thanks for the info. I hope they'll be okay. I think maybe I'll put them in a little tank with water and wafers and put it in a slightly sunny patch, to encourage more algae and whatnot for them.
Also, thank you! It was very hard to let them go, especially since they were a part of the family for so long. But I know they're much happier in their new home. ^_^
If you're planning to use the stress coat as your water conditioner, make sure you get stress coat plus. Regular stress coat doesn't condition the water to remove toxins. If not, you'll need some water conditioner as well. Prime is one most users here will recommend.
There are water quality tests for pH, ammonia, all that good stuff. Not sure where you get 'em though... I've used them before, pretty simple and easy. Basically you put water in a vial, drop in the pill/tablet thing, mix it - don't shake! - then compare the color to the colors on the sheet.
I would also recommend that you buy the meds that your betta need in the future! Betta's always get the disease called "Fin rot" it is very devastating to the fins of the fish the bacteria eats the fins of your fish. Having the meds already will be good it will not stress you and the fish also, have fun with your new betta!