Strange query as source for datagrid

I have a table which contains job vacancies.

The 2 fields concerned are "JOBTYPE" and "WAGE".
JOBTYPE can be either "Permanent" or "Part time".
WAGE can be either per annum e.g "15000" or per hour e.g "7.50".

On the search page if the user chooses to search for both Permanent and Part time vacancies a drop down appears showing minimum wage in per annum format e.g "10000", "15000" e.t.c.

I need to be able to query the table for all vacancies where WAGE > drpWage.selecteditem.text but I also need to search for WAGE * 2000 > drpWage.selecteditem.text in the case of Part time vacancies.

How can I join the 2 above so that I can use these as a source for a datagrid and what is the correct sql syntax for "WAGE * 2000". I have never performed math operations in SQL.

TIA