I’m their new mother

I’m currently house sitting and they have two turtles maybe the size of an Oreo cookie. They are in a tank on the screened in patio. It is currently 58 degrees and will be colder tonight’s so I got them a basking light. The person at the pet store said the water shouldn’t get under 65 degrees and I should leave the light on 24/7 since it’s so cold out. The owner isn’t well versed on turtles and nor am I. I think their son found them in the wild. I asked if I could have them and she said yes.

I plan to move them into my house when I finished staying here. What are some things I should get? Is this basking light okay to sit on the tank like this? It smells a bit hot and I’ve only had it on for 10 minutes. Should I release them back into the wild? Please help! Many thanks.