my DL speeds range from 0-20, but mostly around 4-5. Any ideas on what I could do to speed it up?

1. OS version? Windows Vista
2. What firewalls you have? Not sure
3. How much ram? 504MB
4. Hard Disk space available? 82.3 GB
5. Connection type? (eg: dialup, broadband, cable, etc.) wireless broadband
6. Modem & router brand name & model numbers? clearwire RSU-2510-SV
7. Where are you trying to connect from (house, appartment complex, school, student accomodation, work, etc.)? home
8. What version of LimeWire (LW) & Java do you have? (Go to LW's menu Help>About LW...) Will show both LW & Java version. LW 4.12.11pro/ java 1.6.0-rc
9. Who is your ISP provider (Internet Service Provider)? clearwire
10. Do this simple test for us. Using your browser go here: http://www3.limewire.com:6346/ The page should say 'Your test worked!'. What happens when you go there? your test worked
11. Are you sharing the connection with other computers or p2p sharing programs? If yes, please give details of set up. no,no
12. Is this a your 1st try at LW or is this a new problem with an experienced user. I've had LW for 2 weeks
13. Do you see a brick wall in front of the blue world icon at the bottom of LW's interface? no