Your issue is wifi signal. The easiest way to tell this is:
Right click on your wireless bar on the task bar
Click on open network and sharing center
Click on adapters
Right click on your wifi adapter and select status.
You will see a screen like this.
As you can tell, I have perfect signal but my connection speed is 72Mb/s. I'm on a 300N capable router and wireless card. If you have a lot of interference in your area, you're using the FiOS wireless function on the modem/router, or have a low signal that number is going to be low. If that number is lower than 72Mb/s you are going to have issues downloading. For instance, 54G (54Mb/s) at max signal will download around 2.5MB/s which is the max cap of 20Mb internet. Since you have 30Mb FiOS that is limiting your actual internet speed.
2 things to think about here. If you're using the FiOS wifi on the modem it has horrible speed, range, and runs rather slow. Your adapter is also USB, so you won't get the best signal or rates with it despite signal quality. Other things using the 2.4Ghz band will also affect speeds like microwaves, wireless headphones, other wifi around your house, ect.
If you can, I suggest taking the USB dongle back and getting a wireless card with at least 2 antennas. It will have a "Multimedia/gaming" mode which will run it at full power always. You will get the best speeds this way.
