2.4Ghz or 5.0Ghz band, or both?
As markysharkey
indicated, a site survey would be a good idea to get a sense of the coverage you have now with the 1242 and 1131,
then reposition the antennas accordingly.
As you're not using a WLC-based setup, roaming is in the hands of the wireless client (laptop, tablet, etc) itself, so it's a bit of
a crapshoot and all you can do is maximize your coverage with your two existing APs
My 00000010bits
Regards