I access the site from a variety of locations either dedicated T3 w/10/100 switches or at home via 768 DSL. Much of the time I find the site to load *abysmallyl* slow, with graphics often hanging for long periods of time. I don't know what you're running for a server, but I suspect that PHP isn't the bottlneck. You're not stuck on a wintel box, are you?
Depending on your needs you could move it inhouse. I also use an external ISP for some of my sites (
www.westhost.com). They are reasonable and robust in my experience, and support MySQL.