As long as members have added their location information in properly, and it's something that can be registered as a correct geo location, they should be able to be searched by location within the regular search information itself. If hobbies are listed within the About Me portion of the profiles, then hobbies are as well searchable by the regular search element. The idea would be to create a question within the about me section that asks for hobbies, and then from there, people who have listed them will be found when others search for it.
There isn't a way to add any more drop boxes for the advanced search other than those that are already offered. If you want to search by location, be sure that you have the location checked within the features settings for the member listing page.
