access point not getting expected DL speed

My current modem is Motorola SB6141. Main router is Linksys E4200 .

Connection is as follows:

Port #1 Computer 1 via ethernet
Port #2 Computer 2 via ethernet
Port # 3 Linksys 10/100 Switch > Printer, Skype Phone, ATA for phone
Port #4 Extension to Family Room via cat6 to Trendnet 10/100/1000 switch > Various Entertainment boxes like WDTV Live, TV, Cd players and Logitech Touch

Wifi : Laptop in same room as main router , connected via 5Ghz

DVP Pro 11 tablet also using 5Ghz band , 40Mhz

ISP is Comcast with Blast so download speed is somewhere in the vicinity of 60mb/s via ethernet and slightly less via WIFI ( 50+ mb/s for both Laptop and Tablet)

I use 5Ghz band because its completely free in my neighborhood whereas the 2.4Ghz band is quite crowded.

The signal strength is weaker in the family room and unusable in the bedrooms and in the back porch. This is a single storey house .

I added an Access point in the family room for better WIFI performance with a Linksys EA2700 refurb router configured as access point . This is connected to the Trendnet switch in the family room via ethernet .

The problem is that I am getting only half the DL speed ( around 26Mb/s) from the EA2700 via WIFI whenever either my Laptop or the DVP 11 pro is connected to the EA2700 but I get the full speed when it is connected to the E4200 . I use Inssider to check connection.

I configured the EA2700 manually both ways . a) Bridge mode in LAN-LAN with new GUI b) Rolled back the firmware to Classic GUI and set it up the traditional way by disabling DHCP and setting the IP . In both cases DL speed is only 26 mb/s. I check the ethernet cable going to EA2700 and also the Ethernet port of EA2700 and in both cases I get the full DL speed. Its only via WIFI that I get 1/2 speed. BTW the 5ghz operating freq of the main router and the access point are really separated so there is no possibility of overlap. Both use the same SSID and pw.

Talked to the Linksys tech support and got nowhere after re-configuring the wireless freq , bandwidth . Disable WMM etc etc . No matter what we tried , I still get no more than 1/2 DL speed. BTW during all these tests all other devices connected to the network are off .

I finally returned the router because I think there is something wrong with the EA2700 .

I am thinking of getting another linksys router . Probably EA3500RM or EA4500RM .

I can use them as primary router if needed and I know for sure that my old E4200 will give me full download speed.

Any advise what to do or suggest alternative routers for use as access point

Thanks.