The SerialMonkey rt2x00 open source project (yes, I know its a weird name) makes improved drivers based on the ones Ralink distributes for Linux. They work very well, but are still under development, so sometimes a driver with problems might slip into the downloads section.
I've singled out one thats worked perfectly for me, and uploaded it. But before I give you steps to install the drivers, I need to ask if you installed the kernel source code when you installed Vector. You can find out with this command:
ls /var/log/packages | grep kernel-src
What does that command give you?