low fuel light

I have a '97 voyager 3.3 L. Last week I filled up and noticed the fuel guage still showed empty for about 30 minutes after the fill up. Now, while I am driving, the guage shows full but the low fuel light and bell keep going off and on. The car drives fine but the light and the dinging is anoying. Is this an indication that there is a problem with the pump or is the gauge float in the tank a separate item?
Thanks!

According to this site:
http://www.autozone.com/az/cds/en_us/0900823d/80/1a/43/1d/0900823d801a431d/repairInfoPages.htm

The sending unit is serviceable but looking at the sites of napa, checker, and autozone they only have the complete unit available. You may have to check with dealership to see if sending unit is available seperately.

Good Luck