zarms

hello all, i have in the past used a voip system and decided to cut costs and thus went to a number of magic jack devices. i am now looking for a sophisticated answering software. i have two lines. what i assume is the following, in actual installation i will need to install a piece of hardware to allow the phone wire to connect to the computer, (what is the best for this) then install the IVM answering software. then back out the computer to a phone, headphones, microphone, etc. to be able to listen, talk, or answer the calls. another idea is to use some of my polycom ip phones with the IVM software. what i am missing are the details as to connectivity. as in the phone wire in and the calls out. what are the pieces of hardware do i need to accomplish both scenarios. this might create more questions than answers but i would appreciate any direction or thoughts. thanks in advance, charly