or you can buy a custom antenna and replace the one that came with your equipment
TP-Link TL-ANT2408C Omni Directional Indoor Wireless Antenna 2.4GHZ 8DBI - TP Link - TL-ANT2408C
unless you are in need to repeat that signal for a huge house, getting that is good enough in most cases.
you can price match it with ncix for a lower price too. use shopbot