Since wireless -b, -g and -n are all faster than typical cable Internet speeds, getting a faster wireless setup (wireless adapter plus wireless router) likely will not help.

A test: Disable the wireless adapter and connect the laptop to the router with a standard network patch cable. Does the problem persist? What's the model number of your Toshiba laptop? What OS are you running?

To learn about wireless standards and speeds, try the websites for the major wireless router makers: Linksys, D-Link, Netgear, etc.