I'll add to what others have already said. If you are testing using wireless make sure the network card in your computer can handle faster speeds because if it can't you'll never get the speeds you want. Also what router do you have? If its a g router wireless speeds will only go so high. Mine caps at 25 mbps because of my outdated card but on wired connection I pull an easy 60mbps on a 50/25 plan with the old Westell g band router.
Also check out your routers settings. What one do you have? If its a newer rev. 1 make sure the security is set to wpa2.