|Holly smokes batman. You are only getting about 4x Dialup. What is your Service Level Agreement with your ISP. If it is 1Mb then I would be chewing them out.|
Also, do you have any other devices like a wireless router? If so then try bypassing it to see if it is the problem.
One last thing that might be screwing you up is Bots, Viruses and Spyware eating up your bandwidth. Do a Netstat -b to make sure you do not have any programs you can not identify which as a port open to the internet.
netstat -b > port.txt
if you want to save the report and post it.