My tests on my iPad have been done using 2 Apps and 2 speed Websites. I use to run the same test site on my MacBook and Wife's Windows Vista laptop and all showed similar down/up speeds.
* What type of AP or router do you use for Wi-Fi?
* Is is dual band, or dual SSID (private/open)?
These were some of the issues I read about Wi-Fi speeds back when the iPad was released... You might want to visit your local Apple store and make an appointment at the Geek bar (I mean with a Genius); however I recommend using SpeedtestX HD on some other Wi-Fi networks, like Panera, McDonalds, etc. or even at Apple store first to troubleshoot your Wi-Fi speed issue a bit more.