TelCel SIM card

Our SIM card is probably 5 years old. One of us has to do a very fast trip to the US to pick up new boards, and we can't figure out how to tell if it is 4.2 or better so we can use it in the states.

Help please

Isn't a new SIM card less than MXN$50 pesos? Can you keep your old number if you buy a new SIM card?

The asistentes at the phone stores have always been very helpful. Stop by and ask one.