Newbie has question re: Plantronics Voyager 510SL

[frenchlover]

Hello all,

I'm new here and will stick around since I have much to learn. I've exhausted myself searching online and asking salesmen at every electronics store around. So perhaps someone here can help. Here is what I need:

I'm a mortgage broker and spend lots of time in my office on the phone. I need to use my office phone which is an NEC. I also need to use my computer to receive phone calls (from a different #). I also wouldn't mind being able to use the bluetooth capability on my Treo 700p. Now, I realize that I need to get a Bluetooth USB adaptor to plug into my desktops USB port.

My 2 questions are-

1) If I get the Plantronics Voyager 510SL Bluetooth Headset with the lifter, can I use it with all three?

2) The package that I want has the Voyager 510SL headset, the deskphone adaptor to make my office phone bluetooth and the lifter to attach to my office NEC phone. However it doesn't come with the Bluetooth USB adaptor. So, if I buy a different brand will it still work?
If so, can someone here suggest the best quality one to get? I noticed on Plantronics website that they sell the same headset with the bluetooth USB adaptor but it doesn't come with the other components that I need. If I should, then how can I buy the Plantronics brand USB adaptor separately?

I hope my questions are clear. Thanks for any help that you can offer.

-Frenchie