GPS library for Proteus
I have found the solution to my question so I thought to post it here so that others could also get benefit out of it. Here's the link to GPS Library for Proteus - A complete step by step tutorial on How to download GPS Library for Proteus.

From this link you can download the GPS Library which you need to add to the libraries folder of your Proteus software and you will have the GPS module in Proteus and you can design your simulation quite easily. More details are given in this link.