I have downloaded LW for Mac OSX, I used it the first time and it worked correctly no problems whatsoever, The next time I use it I double clicked on my LW icon it opens but then after having the LW window open for about 20 seconds it then closes automaticly, I have tried to re-install LW but no result, please help.

Try these 2 things:
1. SAFE Boot & Repair Permissions

2. Delete the LW preferences folder found here: /Users/your_username/Library/Preferences/LimeWire

Tried to upgrade and was declined, checked w/bank and funds available? Can someone at limewire help? really like your product and would like to upgrade, help.

Sort out your problem with LW basic 1st before upgrading. Other than what I suggested above to do, also do this SAFE Boot & Repair Permissions