Most recharge wala guys have a cutter. And they will cut your Sim for you for a fee. It ranges from 10/- to 50/-. And if you go to the airtel gallery, you will have to surrender your current Sim and they will issue a replacement micro Sim in a few minutes for a nominal fee, could be upto 99/- bucks. And you might need to submit a copy of the document you used to purchase the original Sim (Vodafone had me submit mine). As for the 2 sims with the same number part, you will have to ask the gallery or customer care, though its highly unlikely you would be allowed that.