I have raised baby painteds and they are soooo cute!
I suggest that you buy the long tube UVB light for this turtle. It will really help with shell growth. Painteds don't need temperatures too warm (they are hardy beasts!), but you could put an undertank heater on your tank to warm the water.
The heat from the UVB lamp will be plenty for the overhead. You can purchase those sticky thermometers to monitor the heat in the water and above it near the basking area.
Make sure to provide a place to climb out and bask in the UVB bulb.
One last note: be careful of any fire hazards. Don't put the tank on fabric or have anything flammable near it.
Let me know if you have any more questions.
PHKiwi