My ping is drastically slower using Wi-Fi?

I just had internet installed. Download speed is 5mbs and upload is 1.5mbs. While plugged into the router/modem, the ping is around 60-80. While connected to the wireless via router, the ping slows to 400-500. This is with only one device connected, internet not in use - simply testing the speed using speedtest.net

The router is in the center of the house, and I use my PS3 from one side of the house. The way things are setup, it's not possible to run LAN cable from router to the PS3 -- I do know that would be optimum. My question is, is this decrease ping speed just because of a poor router? The speed tests are done with a laptop and an iPhone, both within 2-3 feet of wireless N router.

If this is a router issue, please give me a suggestion for a router that won't suffer latency issues! Preferably something under 120 that will have decent range.

Added (1). I understand that the ping will be slower, but I shouldn't expect the ping to decrease from 70 to 500 just from switching from LAN to Wi-Fi, especially withing just a couple feet of the router. I have connected my computer to other wireless networks and have seen speeds as fast as 20ms via Wi-Fi.

To the guy that said "Seriously". Yes, seriously. I don't expect my speed to decrease that much, somethings not right.

Added (2). Once again, I can't run a LAN cable from the router to the PS3, that'd require drilling holes and fishing the cable through the walls and up a flight of stairs, wireless is my only option!

Are you serious?

You are wondering why your Wireless is slower than your direct connection to your router?

You can have a ITerNet cable made to the size you want at any computer shops as a WIRELESS connection is always slower than using a ethernet cable just me sure the length required and have one made up Other way is to get a phone extension from your master socket to the router so you can move it hope helps you as do pcs