I was so in your shoes a year ago. We came home from the beach at the end of July last year with a RES. I was totally deceived in the shop where we bought "her". We call her a her, because we were told she was female when we bought her. After the fact I found out you cannot tell until they are at least four inches long, but she will always be a her to us.
Anyway this is definitely not the cheapest way to go, but I bought the zoo med double dome lamp fixture (there is a mini, so that may be what I have but I think I have the regular one) and then bought the light stand like slider keeper mentioned to hang it on
http://www.zoomed.com/db/products/Entry ... E6IjAiO30=http://www.zoomed.com/db/products/Entry ... RpbmciO30=I would also raise the water level as other have suggested.
I would buy a screen lid, but I would not put the light on it. That is what I originally did. Angelina was not basking. Once I got a thermometer for the basking are I realized why. I was trying to turn her into turtle soup. The temp was about 107 in the basking area with the light sitting on the screen lid. She wouldn't go up there, because it was too hot. That is when I bought the lamp stand. Love it! I can adjust the temp of the basking area just my raising or lowing the stand (it is adjustable). If the water level lowers from evaporation I can lower the lower the stand to keep the correct temp until it is time for tank maintenance.
As for feeling, babies should be fed pellets and veggies everyday. Once they are yearlings it goes to pellets everyother day and veggies everyday. Rule of thumb is to feed the amount of pellets that would fit inside their head only. Do not include their neck. Angelina was getting four or five of the baby pellets but she seemed to be growing too fast. Her shell was looking like she was being overfed. At that point I took her down to three baby pellets a day. Now that she is a year, she gets three baby pellets and one koi wheat germ pellet everyother day and veggies everyday. There is some great info here
http://www.redearslider.com/index_nutrition.htmlThese people here are a wealth of knowledge. Feel free to ask anything. More than likely someone will know the answer.
I'm not sure how big YES grow but the rule for a RES is 10 gallons of water for every inch of shell. With two turtles, they will outgrow 20 gallons fast. When you upgrade, if you can, I recommend going as big as you can. Angelina started out in a 10 gallon and in January moved to her forever home of a 125 gallon tank with an FX5 filter. I bought the tank from craigslist, so got the tank and stand for much less than if I'd bought it new. The tank, stand and filter were a $500 investment, but I should never have to do an upgrade for her no matter how big she gets.