How can i receive more connectivity from a wireless network?

I'm using my school's wireless internet( i'm using it legally because i'm the student of that school) and my apartment is near the school. I can get only one green bar and that's it. Although i can connect to the internet and stuff it disconnects from time to time and I'd like to increase the connectivity. I'm using a desktop and my wireless usb adapter is a wireless-g. I've heard that wireless-n adapters are better. What are my options?How can i receive more connectivity from a wireless network?
my opinion is, you need to hack your adapter. Do a search on homemade wifi antennas and that will give you some ideas. the antennas in those adapters are notoriously horrible for performance. my suggestion is to see if you can make a reflector you can attach your usb adapter to since the antenna is most likely built in. Use a USB extension cord to connect it to the computer, put the adapter in the reflector and point at your school. the reflector makes the signal directional and intensifies it, making both transmit and receive signal strengths better. Like a mini satellite dish. Check the link below. I've made these before and they work pretty good. nothing some postcard stock, glue and aluminum foil won't handle.