US stamping in Matamoros Mexico

[Nautanki]

Hello,

I am planning on going to go to mexico on Aug 17th. As per the appointments it seems that you should have your ASC (Biometric finger prints done a day before your interview day and you have to schedule that too.) My question here is

1) can some one give me an estimate if three days is ok for this entire process.

2)Do I have to stay in Mexico during this process?

3) do I need to apply for any sort of visa for entering the mexico

Please note that I work full time for a engineering firm.

Any prompt and useful information would be helpful.

Thank you