Good to hear your internet connection is fully functioning.
I had the exact same issue, And after a visit from my ISP, A new modem was supplied as my one [Which was around 4-5 years old by now] had given in.
the new modem i have is 50 Versions higher than the original modem i had.. And my conenction speeds are faster than usual, meaning i have been ripped off by my ISP for the past 5 years, paying for connection speeds that i never got due to the Old modem they supplied me with, Business' aye? Evil.
Your speed isnt based on your modem that just means your old modem was so crappy it wasnt giving you the full speed you were paying for... Your direct internet speed is based off what your isp sets not your hardware unless your net isnt limited but thats like never the case unless your paying 10,000 a month for a direct line to a backbone setup for mostly hosting...

In short you have more speed with your new modem vs the old one because the old one wasnt powerful enough to read and send as much data as you were sending and requesting at the time.
A good example is computers say your playing battlefield 2 and your only getting 30frames a second then you replace your video card and now you get 60 frames per second your computer was able to do more it was just limited by some part of your hardware. Thats as simple as I can explain it.
Pfff. I lost internet completely yesterday - as some of you MIGHT have noticed from being absent from prpr - and so we called up the comcast people. They reset it and all the lights went on... and then then the internet went out again lawl. She also said our modem had a terrible history with disconnecting. It d/c fifty times in one day alone. So then a guy came out today and set up a new modem for us, I guess. XD ALL BETTER. As I'm obviously online right now.
You should still call tech support and have your modem setup to a bridge mode then make your router your main pppoe connection.