Networking isn't my area of expertise, either.
Two things you can look into though are 1) what is your DSL services up/down speed, and 2) are any of the requests being redirected through any internal proxies/firewalls?
If you have a network administrator, you would be better off talking to him/her about it. Also, Fiddler is a very useful tool, as well as wireshark (although the latter is for someone more experienced in debugging network related issues).
That's about as much direction as I can give, sorry....
Lance