I have Comcast and am currently still renting the Arris TG862G modem. I do have the triple play package (internet, cable, phone) so that really limits my options. My main question is what would you recommend for my internet setup. I currently have the Arris TG862G modem and am using its wifi along with a separate router (old linksys that I will replace). I should be getting 25up/5down but am not usually reaching anywhere near that and all of my devices run very slowly. My household has many devices that are in use at varying times (1 wired desktop, 3 laptops, Wii, Xbox, 3 smartphones, 3 Ipods, 3 perk devices). I will get a new router, probably the TP-LINK TL-WR841N but am open to suggestions. Should I continue using the wifi from the modem in addition to this or put the modem in bridge mode? If I should get another router or a better one, I am open to suggestions. Thank you in advance.

Edit: I forgot to ask, should I look at getting a dual-band router? I don't 100% understand the pros and cons of them so don't know if it would be worth it or just get two cheaper ones.