The 21-year-old has made four appearances for the Hawks since joining on October 6th, and will now be available for a further four matches.
Lyons-Foster joined The Shots in the summer.
He had been with Bristol City since June 2016 following his release by Aston Villa, but failed to make a first-team appearance for the club.
He joined Bostik League South side Guernsey FC on loan in December 2016, before a trial spell with Irish side Derry City in February.