Admin has disappeared

The link to admin on the upper right hand corner at www.skivermontqr.com has completely dissappeared in IE8, Firefox and Safari. In IE I can get to the login via http://skivermontqr.com?q=user/login. But whrn I attempt to login I get Internet Explorer cannot display the webpage(similar errors in Forefox)

My hosting company has suggested manually clearing the cache.
How do we do that?

I desperately need to get in there.
Before this happened I had taken the map off my contact page, and added a photo field to a basic page.

The time on the server has been increased to 90 seconds but the pages still load INCREDIBLY slowly.
I have a watchdog .csv file to look at also if that will help.