As it says on the page i sent you to
"If you look at the top of WinMX you will see a button labeled "Settings" - When you click that the WinMX settings window will open.
First select "Bandwidth Throttle" on the left, then it will switch to the Bandwidth Throttle page shown above. Make sure the first tick box is left unticked, and tick the second tick box. Then enter 30000 in to the box next to it.
Click "Close" to close the Settings window... ITS AS SIMPLE AS THAT!
If you find these settings dont work for you, then try setting it to 28000 and see if it improves it, however if it doesn't then dont forget to change it back."
The numbers used here are an example but adjusting them will give you best performance in your case whatever its set to needs to be reduced to slow the uploads which in turn should speed up your downloads