My first suggestion that I always tell people when they're experiencing slow internet speeds is to GET OFF WIFI. :)
Try a direct, wired connection (with an ethernet cord) before anything else and see if it improves.
If not, go here: http://www.speedtest.net
If your speeds are above 2 Mbps, that shouldn't be the problem.
If it's slower than 2 Mbps, you might want to look into upgrading your internet service to a higher speed.
Then head to: http://www.pingtest.net
If your grade is A or B, that shouldn't be the problem.
If it's C or lower, you might want to contact your internet service provider and tell them you've got poor line quality. They may send a tech out to check your lines.
95% of the time, slow internet speeds are due to high volumes of traffic taxing your service provider. Try testing your connection again in the morning or very late at night (at off-peak times).