Are you able to log into the modem, and check out which firmware version you are on?
There is a NEW firmware out.. but may take a day or two to be pushed out to the gateway, which may fix alot of those issues. Some things like that, some users reported prior to this patch.
(Most of those people with issues, were on the previous 150 or 250 plan)
That your PHONE though can get higher speeds... but the laptop, even when PLUGED in.. is odd though..