Reduce my ping

Well, my ping used to be around 47 and was always green but recently it has been yellow around 300-400. I did speedtest but it was fine but when i go on GW it is high. What is the problem. Could my PS3 or Xbox 360 be effecting it?

Comcast uses certain tricks to manage their bandwidth, and for many, online games are unplayable, or have very high ping.

There's not much you can do, outside of changing your ISP.

Synthetic tests don't show much, especially if what you're testing is on the same network. Try testing with some distant server (the 50 miles mentioned above is not representative for Anet's servers).

Then why was my ping always around 47 for like 3 months before until lately.

It is because of the festival event.
A lot of people are playing now at a specific time and going to a specific town. That increases the bandwidth load on A.net's servers and causes everybody to lag a little bit.
After this weekend, your lag should calm down again (athough 300-400 is NOT bad lag at all).

300-400 is VERY BAD LAG for PvP, for example, cant interrupt anything under 1 sec cast time. I have same problem like you, and the only way i found to emprove it a bit, is to play PvP from district where i am from (for example, in EU district iam from EU), but its not happy solution for me, becouse GvG's and any quality PvP's is from interanational districts.