A lot of wireless devices in my multilevel house are bogging things down want to improve it.

[netaw]

I'll try to give all the details I can think of.
We have Comcast 25MB connection, My modem is a Ubee U013c105 modem. Netgear WNDR 4500 Router. I have an older multi-level house 2 1/2 stories, The router in within 3 feet of the cable modem. The router is placed High in our living room on our entertainment center, roughly 1 foot from the ceiling. The closest wireless computer to it is within 10 feet, The furthest is 30 feet. These measurements do not take into account obstructions such as walls or ceilings. My son has a very nice gaming computer that is on the 2nd level of our house, and probably 10 feet away from the router but it has a ceiling and a few walls between that machine and the router.
The problem is that without cell phones or tablets included we have 3 smart tv's 3 blue ray players, 6 laptops/computers that are all on the same network, through in 7 cell phones, and 3 tablets, we have a lot of products looking for wireless network.
I have set up a 2g Connection and 5 G connection and devices depending on their connection methods are split up on those. With all of that connected, you can't play a game on one computer, and watch Netflix or Amazon on the other. What i'm looking for is some ideas on how to improve the network in my home and i guess even it out a bit. Give my son enough bandwidth for gaming and let me my wife and I still be able to watch Amazon Prime and cast it through chromecast to our tv. Despite the way it may seem, I don't have a ton of money to throw around, but i'm willing to pay for things that can help.
Any ideas would be appreciated.

 

[BuddhaSkoota]

What i'm looking for is some ideas on how to improve the network in my home and i guess even it out a bit.

The best solution to extend your wireless would be to add a wired access point on the second level. This would require running a Cat 5 or better cable from your current router to a convenient location for the access point upstairs. You can purchase any good quality router and configure it as an access point. If you are able, you could locate the new access point close to your son's room to provide wired access to the network, which is best for gaming. The most difficult part of course is routing the cable and placing jacks and end connectors, but you will benefit from a connection that will be fast and trouble-free.

The next best option is to use power line adapters to extend your network. A pair of power line network adapters uses your homes electrical wiring to communicate, and will link devices much like a wired connection. There are adapters that are available that have built-in wifi access points. Power line adapters can provide a very fast connection, but link speed is dependent on the quality of the electrical wiring in your home, and can be somewhat influenced by interference from other electrical devices. These devices are great for easily extending your network, but you may want to be sure to purchase from a retailer with a good return policy in case they don't work as expected.
Example of a wired/wireless power line kit:
http://www.amazon.com/TP-LINK-TL-WPA4220KIT-ADVANCED-Universal-Powerline/dp/B00HSQAIQU/ref=sr_1_1?ie=UTF8&qid=1414297669&sr=8-1&keywords=powerline+wifi+extender

Wifi repeaters (sometimes wireless extenders) are another easy solution, but these are the least favorable option since they will halve wireless throughput. These will negatively affect high bandwidth applications such as gaming and video streaming. Placement of repeaters is critical since they must have a fairly good connection to the originating router while also providing adequate wireless coverage to deficient areas.