I did this. I thought I was 15 days early, and instead I was 15 days late for renewing the visa -- I had messed up the month. This was 3 years ago, and while at first the people at INM thought they might fix it locally, that didn't work and I ended up having to go to Laredo to start the process over again.
If you're an American, I would plan on a trip to the border sometime soon. Don't know how it works for people from other countries.
Since your visa has expired, you are now here illegally. But in reality that means little -- unless you have official contact with immigration authorities. So if I were you I would try not to attract official attention and plan for a trip to the border when it is convenient for you. The people in Laredo are nice and efficient. I think they now require appointments, but if your papers are in order I think they still can issue the temporal the same day as your appointment (if not, it'll happen the next day).
I don't see how a lawyer will be able to help you with this (I mean, avoiding a trip to the border.)