I suggest you to take a look at the following links, those are article numbers with different recommendations for better performance and connectivity issues:
What are the recommended settings for 802.11n connectivity?
Possible interference by other wireless devices may impact 802.11n performance
Data rate will not exceed 54 Mbps when WEP or TKIP encryption is configured
Regarding the router, the recommendation will be to contact the router manufacturer for further assistance regarding the best configuration of the router.
Thanks I did go through those links but I still have issue with the wireless connection. It will just stuck for a couple of secs ~ 30-40secs and is happening frequently. I enabled wireless event log and I see following error once in a while ( not at the time when the connection stucks )
Roam trigger <BSSID> <SSDI> 161 RSSI=-40 MisBcn=8 RSSITh=-72 Roam other reason.
Any other idea what does it mean and how to fix the problem I've?