Assign an id to a link

I need to assign a logged in users ID (meaning actual id number) For instance if you go into the admin area and look under users, then authors + users you will see a checkbox and next to that checkbox is the userid i am talking about.

Example:
I need to assign the persons user id to the end of this link

http://users.nexusleads.com/click.php?affiliate=1016&campaign=1&creative=3&sid=

In doing so i can track what user clicked on what link. Can some one please help me out with this code, i am willing to pay money if need be. I have asked in numerous places and no one will help me.

This is what i need to happen:

User is logged in. User clicks on ad. The users wordpress id is then added onto the link so i can track him/her and pay him.

Thank you for your help.