Try changing the channels that your router is using, use 11g and 11n only as using 11b will slow it down to 11b standards, (11mbps only)
Using this router in my LAB shows me that it;s actully stronger than others ! So, it may be that you and your neighbours are fighting for bandwidth on the Wi-Fi channels selcted by you.
Channel 1, 6 and 11 shoudl be used, most come as 11 , so try moving to 6 and below.