I have been feeding my daughter ready made similac at room temp for over a week after opening. can she get sick from this?

No: I take it that you are simply opening a can and transfer it to a bottle and feeding it. I don't see anything wrong with it, if the baby is drinking well. Warming the milk is preferable for a young newborn baby because it simulates temperature of breast milk, but certainly it does not sterilize the milk.

Not sure: Storage instructions are usually provided on the bottle near the nutrition breakdown table. I cannot tell you if you can or not, since I am not familiar with manufacturer storage guidelines.