modification to search function in probid website

I have a website running on php probid. We want to complement the site search results with the ones of another website. This other website has an affiliate program and provides access to their products through an xml snippet. I will send you site and login details where you would get this. So, when someone searches through the websites main search query our website should show our results and the ones from the other site(blended if possible). The other sites results are only links to the product url of the other website. I need somebody with experience in this. Let me know of any questions. If you are going to bid please explain your plan for the job.