Was thinking of getting this antenna but it doesn't support 5Ghz band...

http://www.ebay.co.uk/itm/TP-LINK-TL-ANT2424B-2-4GHz-24dBi-Grid-Parabolic-Antenna-/380723362542?pt=LH_DefaultDomain_3&hash=item58a4e17aee

According to the TP-Link website it supports 802.11n
http://www.tp-link.us/products/details/cat-5063_TL-ANT2424B.html

I'm not sure if I should be looking for support that supports both bands because I'm not sure how important the 5Ghz band is? Would it be possible to combine a 3G antenna with a reflector like this...I can see the antenna from the back of my house but the signal is very poor inside...

Thanks.