For the past week my Wi-Fi has been very slow. I have a llinksys router and my hp windows vista computer has been slow, my iphone 4s has been slow, i can't even watch videos on my iphone anymore for it takes to long to load videos. My xbox live connection has been slow aswell so i can tell its my Wi-Fi. The other thing is i have comcast internet. I did some of those internet connection tests and i think i did bad. Heres the link for the first one.

i also download the app on my iphone 4s to see its connnection and its definitely the Wi-Fi since my 3g is faster to load videos. Just to get these pictures to download on the computer it took about 5 minutes, normally it takes like 20 seconds. It takes long to open a new broswer aswell.
i finally uploaded this picture which took about 20 mintues.

how can i find out what the problem is or fix it? Is it my router? Should i call my provider which is comcast? I havn't restarted my router or anything like that either.