As far as i know..No you cannot do this wirelessly. Also if you only have two computers what would be the point other than using router because you have it. One alternative is set up share internet and bridge the 3g with your Ethernet port and run a cable into the router. But I am not even sure if this will work. You can always buy a 3g wireless access point router that works with your thumb stick to act like a mifi spot. But if you only have two computers I say just ad-hoc it.
Um, your answer is technically in your question: ” I have 2 laptops wifi enabled and a wifi router”.. Why not connect teh wifi laptops wirelessly to the wifi router?