Try re-booting your 17" screen (hold down both scroll wheels). I have found over the past two years that the 3G connectivity seems to "deteriorate" over time, and sometimes after a firmware update, but re-booting always brings it back for me.
Did that... I too find 3G droppage an issue apres update. So I did a couple reboots.. and I know it can take several minutes to find 3g and all facilities after a reboot so I gave it that time... but nope. Not after a 30 minute drive did it have enough internet for voice commands, browsing, etc... all the while showing bars of 3G. Couldnt connect to the car (waking up...)..
Good news, after work it was all fine.
someone said 115 does not fix the leaky slacker wifi consumption, so I am making the car forget my home hotspot for now until that is addressed.