New camera recommendations
I don't know if you are in the US, but if you are and want to purchase the 5100, Amazon is selling the body plus the 18-55 for $700. As you said, you will need to buy another lens in the future for sports.
I haven't used the 5100 as I am still hanging onto my D90 until something new is announced. I haven't bought the 7000 as it is already a couple of years old. I hope that my waiting isn't in vain. Good luck and enjoy.