To help answer the question of whether it's your wireless router or your internet service that's the problem you could use one of the bandwidth-test add-ons for the Firefox browser.
Trying it both with the computer wired directly to the router and wirelessly from your usual work location should show you if it's your wireless signal strength that's the problem.
Trying it both with the computer wired directly to the router and wirelessly from your usual work location should show you if it's your wireless signal strength that's the problem.