Modify existing table for more details?

I have a table of estimates. Each estimate can have multiple locations
stored as a text field. New need: I want to store the sizes of each
location. Example is -Old method: EstNo= 200 which has Location =
bedroom, Location= Family room. New need is: EstNo 200, Location
= bedroom with Size= 100 and Location= Family room size = 125. I
assume I need to split the Location field into its own table with a
Location ID field, Location field, location size field and EstNo
field. Also, How would I go about correcting the existing estimates
that have no location sizes entered. Hope I discribed this clearly
as I am a newby.