Expression Building in Access 2000

What is the expression for to isolate dates within a table and maintain subsequent fields in order to total figures for a month on one i/d.
id=1
Date 1=01/01/03 Price 1=?1
Date 2=02/01/03 Price 2=?2
Date 3=01/02/03 Price 3=?2
Total Jan=Expression?