Can I feed my cat wet food AND dry food?  

Yes of course you can feed wet and dry food, although it may a bit harder to control calories that way.  If you want to stick with dry, get your cat's target weight from your vet, and feed the amount of dry per day for the target weight, not the current weight.  She should lose weight that way slowly and safely.  You can divide the total among as many meals as you want, taking care that she does not go more than 12 hours between meals.  BUT if you stick with dry food, use a high quality low carb food, and you MUST go out of your way to make sure she drinks plenty of water, leaving her several sources, and try to get her interested in drinking out of the sink/tub faucets when you're home.  The key is for her to lose weight slowly and stay hydrated.  So if, for example, her target weight requires 3/8 cup of dry food per day, you can divide it up into three 1/8 portions.  You can still give her treats, but keep it to only a little (like 2) at a time.  Ignore her pleading eyes.