Prices of products i added are showing zeros

hello simon and alex. you guys are doing a great job and i trust you will help me resolve this problem. the prices of the products i added are just showing zeros. i use 1.6 version of the startcommerce but then i got the 1.7 version which i uploaded to my theme section, unfortunately, the homepage is blank expcept for the logo i uploaded, so i reactiviated the older version of the theme. mi question is how do i upgrade the older version to the newer, is there somethign else i have to do to resolve this?

http://wordpress.org/extend/plugins/ready-ecommerce/