I have one another solution, why not try to reduce your costly downtime, get instant alerts as soon as your website is unreachable or faces downtime. APlusMonitoring (www.aplusmonitoring.com) is a solution for your whole company. The service monitors your website, server availability and performance externally from our worldwide network of monitoring locations, 24/7 and every day of the year. When your website or network fails to respond, we notify you instantly via Email, SMS/Text Messaging, RSS so that you can hit the right chord at the right time and fix them before it costs you money, customers or reputation.

I personally am using the paid service from aplusmonitoring.com, the price range here are very much affordable.. it also provides free lifetime service with 1 hour interval, all you have to do is register on the website.

I would recomd you must try it.