BleepingComputer.com: Bandwidth spikes, slow internet

Hello all.

I take care of basic IT for a small company, lots of hardware related issues, Windows problems, network issues, etc. Normal day-to-day computer problems. We have a bundled T1 phone/tv/internet business service through Time Warner, with 1.28Meg committed for data at any given time, and max data bandwidth of 3Megs (when no phones, etc are being used). The issue is this: there are times when internet browsing will just crawl. I have locked down on streaming radio, and other bandwidth hogs the best I can, but we are still having this issue crop up from time to time. When I place a trouble ticket with Time Warner, they tell me that we are maxing out our bandwidth with "spikes." When I look at our usage log, however (via a Sonicwall firewall), we have only used 450 MBytes of HTTP transfer in the past 23 hours, 12 MBytes of HTTPS, and it just goes down from there. This doesn't seem to be what I would consider abnormally high usage, however, if we have these "spikes" as Time Warner claims, I need some help in finding what might be causing this issue before we purchase an additional T1 data line from Time Warner. Any ideas, advice, or help?

-joshua