The Contacts module screen shows an overview of your contacts - from here you can perform basic searches but if you wish to search on more than one parameter then click on Advanced Search
Within this Advanced Search window you can search on many parameters for both contact and company criteria at the same time which enables you to be very specific about your search.
e.g in the example below I have search on 4 parameters from both Companies and Contact information. You can make these more or less specific using the AND/OR options in your search criteria.
Once you have a list of the resulting contacts (very small in this case) you can simply export their details to excel by clicking on the export button highlighted below.