You didn't indicate how much ASP coding there is, but you should probably consider modifying the code to PHP. It's more portable, which will help you in the long run should you ever decide to move the site to another host.
If it's a large site and converting to PHP would take a significant amount of time, you might consider purchasing a copy of ChiliSoft ASP (http://www.chilisoft.com
), which will let you run ASP on Linux servers. Your hosting service would have to be willing to install it for you, but if they have other customers that would benifit from both PHP and ASP they might be willing to pick up part of the expense.