I have 3 girls almost the same age (except my youngest is now 11 months old and sleeps 12 hours....so hang in there, it will happen). When my oldest was about 4, she used to wake up in the middle of the night on average 1-2 times a week, with either growing pains, bad dreams, or just couldn't sleep. I would simply walk her back into bed, and either rub her legs, tell her something nice to think about (swimming, school, going bike riding, etc...) and then say, I love you, night night. We NEVER let her in our bed, because once you let them in your bed once, they will want it all the time. We have never had a child sleep in our bed....ever!! I would rather lie with them a couple minutes in their bed and then leave (when they are still awake), so they keep the skill of putting themselves to sleep. That lasted for a good year, now she simply gets up to go to the bathroom on her own, but goes right back to sleep.
Good luck!!