Wireless hookup for Internet

http://www.amazon.com/gp/product/B001QVQ7JU/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539

Do I understand correctly? Will this unit hooked to one of my HR20 HDDVR units allow me to access movies thru Demand without anything else or do I need something hooked to computer router or modem? Thanks