I just thought i would copy and paste some websites to you that I provided on another answer about last names.... hopefully this will help.... you can play with different generators and keep the first name Christina as the surnames change. i would also suggest a word play or rhyming dictionary.
http://surnames.behindthename.com/
http://www.seventhsanctum.com/
http://www.squid.org/tools/random/index.php
http://www.namator.com/names_people_a.php
http://www.rinkworks.com/namegen/
http://identitygenerator.com/
http://www.fakenamegenerator.com/the-sims.php
http://www.voidstate.com/name_generator/index.php
http://www.chaoticshiny.com/namegen.php
http://www.brenz.net/services/randomID.asp