Custom Search - Admin interface & Affiliate linking

Background: I am an affiliate of a number of companies/warehouses selling physical products. Their sites offer many products. I am developing a site where visitors will be encouraged to search for these products and then, of course visit the sites through my affiliate links. Looking for: Some form of custom search function that will enable visitors to enter their search term and the search will be performed only on the sites that I specify rather than the web at large. When the search results are returned and the visitor clicks on a link, the visitor must be sent to the site through my affiliate link. I am aware that Google custom search enables us to specify which sites to search, but that's as far as my knowledge goes. Admin Interface: The admin (me) must be able to add/delete sites to be searched and the relevant affiliate link to follow if a link from that particular site is selected. Main Considerations will be: 1. Effectiveness 2. Ease of use - ie. simplicity of adding and removing sites and affiliate links 3. Ease of installation (I am familiar with installing scripts, building simple web sites, ftp and cpanel) - the installation should be simple enough so that I can install on any site I wish). Job type: Since I don't now all the possible solutions out there or the skills required, I am not sure which category it falls into. Budget: Flexible and open to reasonable proposals. I have classed it as a small budget simply because it seems to me that we're talking about an interface with Google custom search as an appropriate solution. I recognize though that my tech knowledge is limited and that this may not be the best solution or the work may be more involved than I think. I am therefore open to logical alternatives.