Advanced search

Hi all,
I need to make an “advanced search” for a website I built using U-design theme :
Search by
Zip Code
City
Here is the link to the website and page (now there is a placeholder where the search should be):
http://www.epos.org/parents-patients/find-an-epos-surgeon

I have some knowledge about PHP/mySQL but I’m newbie in backend development

I’d like to know how to achieve this kind of search by custom fields etc – if you know a step by step tutorial that would be great.

Thanks in advance!