Delivery Costing Solution - creative + Simple (required)

[el_jackson]

Hi,

Thanks for reading this - we're after a genius "delivery costing" solution

Situation =
UK asp website, viewers can purchase products online
worldwide delivery
Standard checkout software
our simple d'bases calculate delivery prices

Problem =
Want to add a second choice for delivery, but, dont want to add another huge great big database of prices

Idea =
http://www.interparcel.com/quote/
somehow, we want to punch out of our website, to this one (or similar), use their d-bases for our customers to calculate shipping prices

difficulties=
ability to "pre enter" delivery country in the "drop down box"
ability to pre-enter" the package size

Not a website expert here - simplicity appreciated.

thanks