Speedtest.net uses a Flash based byte counter and it's notoriously inaccurate for measuring true download and upload speeds.
The one speed test site that most serious testers use is at testmy.net, which uses only your browser for the test and allows the user to run separate download and upload speed tests, and allows the user to select a fixed file size for those tests...never use the "SmartTest" option if you want true accuracy in your speeds.
If you go to the web site below, run two separate tests..click the "Testmy Download" button and when that page loads select a 25mB or 50mB file from the drop-down box as your test size and let it run...
Then, go to the "Testmy Upload" option and select the 17 or 23mB file from the drop-down box as your test size and let it run..
You can post those results...if you run these tests early in the morning when fewer customers are competing for bandwidth on your ISP/Internet connection, then run them again during the peak-use hours of 7-10pm you will have a fair picture of how congestion effects your speed.
http://testmy.net/