Assist in configuring securepay.com.au shopping cart with Joomla 1.5, Virtuemart 1.13

Hi, We are trying to integrate [login to view URL] into a website built using Joomla 1.5 and Virtuemart 1.13. [login to view URL] is an Australian product (based on [login to view URL]). We are using this payment module for VM: [login to view URL] However, we've hit some problems, and are having trouble getting it configured correctly. Please respond with an indicative cost (or hourly rate), and when you could commence work.