Actually, any brand of wet and dry food is good for kitty. As long as it's a good quality and kitty will accept/eat it. I give my cat who is 13 wet food twice a day and leave a bowl of dry food out for her so she can eat during the day. Fresh water is a must, especially in the summer time. Milk isn't good to give all of the time. It's ok to give once in a while as a treat.
If kitty doesn't care of a particular brand of wet or dry food. Write it down so you won't forget it. I do this so I can remember what not to buy my cat for food.
You can choose any brand of litter that you think you will like. Once you do choose a certain brand, stick with it. Stay with the same brand of litter as cat's can't deal with change. They are very fussy when it comes to their toilet needs. Don't move the cats box around either. Keep it in the same area at all times. If the box is moved around a lot, it confuses the cat and might make kitty go else where in the house. Make sure the box is clean at all times. Cat's hate dirty boxes and will refuse to go in a dirty box. I can't say that I blame them either. I know I wouldn't want to go on a dirty toilet. Scoop out poops every day. If you use a clay litter, wash the box out with hot water and a little detergent once a week. Dry it real good and fill it back up with fresh litter. If you use a clumping litter just scoop out poops and pee's every day.
My cat loves some human foods too. She likes a variety of things that I eat. I'll give her a little taste of the filling in Devil Dogs or a few pieces of cheese pop corn. I don't let her eat the popcorn kernel tho. It is fine to let them have a little treat once in a while.
I hope this advice helps you with the care of your new kitty. I think it's wonderful of you to take her in and give her a nice home. I'm sure you will have her for many years to come.
I have 15 years combined experience in an animal shelter and animal hospital.