Iams is good as any if she will eat it.. do you mean wet or dry Iams? Some cats like to munch frequently so having a bowl with some dry food always available is good..unless they overeat, but your cat doesn't seem t o have that problem..of course always provide water fresh every day..
and feel free to clean the litter box after every use! My cat usually goes outside, then I shovel it up and toss it in a hole..if it's bad weather, or at night, he uses the indoor litter box, and then I remove 'it' and flush it down the toilet.. (does anything stink worse than cat crap?)
..one more thing; cats will vomit up a meal now and then. don't worry. just clean it up, and take it to a vet if it happens more than 2X a day..
help the kitty keep it's fur clean by flea combing it often, this will help keep fur balls from forming..when my cat vomits he gets a little Petromalt, some cats will lick a little vaseline off your finger-- it helps the fur balls pass -- they seem to know it's good for them.