www.digikey.com is your friend. Type in relays into the search function, pick what kind of relay you need, and then it'll set up a parametric search function. Go from there.
If you want to know how to bump up a voltage from 3 volts to something bigger, you can but together a boost switching power supply circuit, but then again that may be too advanced for you. I did a Google search on boost voltage regulators and here's the
link for that, if you are so inclined to want to learn more.