From another kid related overweight mom who started running again and has now lost 17 pounds and counting-
I went to a running store and they fitted me for shoes and watched my running style (it was a bit embarrassing since I am also not the fleetest of foot). they gave me some recs and I ended up buying something somewhere else, but used their recs. I loved the brooks ghost 5 running shoe the most but ended up with a pair of Nikes that are also very comfortable. I pormised myself that if I stay serious about running for at least 6 months, I will invest in the Brooks.
I was never a good runner, but now am up to 3.75 miles without stopping (felt like I was a gigantic monster running when I first started about 3 months ago and could not runn more than TWO MINUTES without stopping). I hope to do a 10K this fall.
Good luck to you - I feel much better about myself now that I am active again