I believe this song came out in the summer of 1979. It was a disco song by a female artist and the only line I can remember goes something like "Don't make me wait too long..." The song had an awesome percussion/instrumental segment about half-way through and was "classic" for the disco genre. I remember thinking it would pop up somewhere in lists or on oldies radio shows, but noooooooo! Help!
If not the Roberta Flack song (written by Stevie Wonder - listen to a clip here) another with those lyrics but from 1977 is "Girl Don't Make Me Wait" by Pattie Brooks - clip here