I actually got everything working both with the dlink and the Cisco.
I still only have 25mbs download speed, but we are upgrading to 50mbs in a few days.
I never used to have issues with lagging games on my 360, but I guess the Xbox one uses more bandwidth.
I can run my xbone on 25mbs but it takes 15-20mbs out of the 25mbs. This means if someone is streaming something, I lag, and quite a bit. This is where the Cisco came in handy. In the Cisco setting for prioritization you can give a minimum amount of bandwidth that is always goin to the devices on the priority list. So I put my Xbox one on the list and set it to always have 15000kbs, and since then I haven't had an issue.
The down side to doing this is it only left the rest of the house with 10mbs, and this is why we are upgrading.
And the issue with the laptops, I have solved as well. I had to turn off the 5ghz band, also if you have a guest network, disabling that can help, and also changing the frequency-channel of my 2.4ghz from auto to a static channel. (I needed to try several channels before I found one that worked).
I will be getting my SBG6580 tommorow(I hope). I will call my ISP, and have it set up and upgrade my plan. Then all I should have to do is put the modem into bridge mode, which I have been reading a lot about as well. I would use the internal router/wifi but I bout a Cisco E1000, Cisco EA3500, CiscoEA6500, And a DGL5500. So I might as well use them, I'll probably sell the rest online to get some money back.