Having trouble using wireless.

   I have a desktop with Ubuntu (an earlier version from late 2007). I have no phone line access to plug the computer into. Everyone here uses WiFi/ WLAN/ Wireless roamng. I am located in downtown and surrounded "hot spots" and by free public access for wireless. I have a library across the street with public wireless access and I even have the security passwords.
   My dongle (sakar from iconcepts) can be used for desktops or laptops. The cd not oly has drivers for windows but also for Mac and Linux. Yet, I can not get online. I copied the linux drivers to my computer. But. it don't work or I did it wrong.
   The support advises to go to synaptic-package to the"ndisgtk" and install the ".inf" from windows driver.
   My synaptic-package has no "ndisgtk" or wrapper. Where and how do I get these? Do I really need to since linux drivers are on the cd? I have not been able to update because I can't get online. I use other computers in building or go to library. I've used my ubuntu computer just for office. But, I'd like to get it online. I can't afford online service provider and everyone in my area gets wireless free access.
   My computer was built & given to me from a program for poor students.
   I have average to slightly above understanding of technology. So, I'll likely understand you if you explain it in technical terms.