for using 2 APs on 2.4GHz these are expected results. i would suggest to get atheros device like tp-link TL-MR22U because ar150 is crap and i wouldn’t expect much more from ar300 too, and run it’s wifi on 2.312GHz, then you will get good speed with rt3070 on any of the 1-13 channels. otherwise be happy with 5-10Mbps speed.