The file you need to modify is the following:

includes -> templates -> YOUR CUSTOM TEMPLATE -> templates -> tpl_product_info_display

You just have to find the section(s) you want to change and them move them around until you get the look you want. Using v1.2.7 is a little more difficult because of the tables. But if you upgrade to v1.3.0.1 things are a lot easier because the sections are clearly labeled with <!--BOF xxx--> and <!--EOF-->.

Making changes in this template file and your CSS stylesheet, you can get the look you want.