" I want to know if there is an easy way to stop my IP address being shown,"
That's not possible.
"...or a way to change my IP address when I login"
If you're a home user then it should be easy. The chances are that the public IP address assigned to you by your ISP is a dynamic one. If so then to get a new address simply turn off your broadband router and turn it on again. To confirm whether the address has changed, use a website like this one.
PS: Proxy servers are great for users that need to hide their real IP addresses but they probably aren't the most elegant solution for your particular situation.