Customize interchange shopping cart software

I found a script at template monster that I would like to be customized with the shopping cart: interchange - the script is located at:? ? <[login to view URL]> the software can be found at: [login to view URL] I would also be ok with a oscommerce instead of interchange as long I was able to get a seamless integration with the template I chose.? I want to use paypal as my payment processor and would like my main page to be my store front. You can view my current site at:? <[login to view URL]> I can install the script on my domain but thats the extent of my knowledge.? I would like someone to integrate the template and set up shipping and other variables into the program so that I will only have to update prces and add new products. Let me know if you have any other questions - I believe I provided all neccessary information for this project. Thanks in advance for your time, Joe