"only" 30kb/s. Bah. Kids are so spoiled these days.
Where is the wireless access point? How far are you from it? How many walls are there between it and your computer? If you're using Windows XP put your mouse over the little icon of two computer monitors, there should be a pop-up that tells you what the signal strength & link speed is; what've you got?
If the link speed is 6 MBPS or better, your wireless link is fine. Don't worry that it's not a perfect 11 (or whatever the max is for your particular type of system), your cable modem can't go that fast anyhow.
Could be there's interference... the 2.4 GHz band that most wireless home networks use isn't just reserved for wireless networking. There are "channels"... you could try switching over to another channel to see if there's less interference in that part of the band. You have to change the channel on both the access point and your computer's network card... no way to tell you how to do that, you'll have to read the books.
Could be the wireless link is fine, and the cable modem is the "problem". Most wireless access points have ports for wired connections too. Try plugging your computer into it and see if the speed is any better. If not, talk to the cable guys.
As a stopgap measure, try some
WiFi Speed Spray.