Asterixk setup for an existing small business (With a twist)

Hello all,
I'm looking for some direction and input into a somewhat complicated Asterisk/Trixbox setup.

I have a friend who is moving his company from a small business park to a new location in another town, with the same area code but a
different pefix (no long distance charges between current City & new Town). They have a world wide customer base and regularly make outgoing LD calls.

I've been asked to help with an Asterisk/Trixbox setup for the new location but they must keep the same phone nubmers, this is my main concern.
Designing the right solution that will keep the current phone numbers but offer the best flexibility.



The setup is as follows:

1. Sales line 999-555-0000 + 1-866 number
2. Support line 999-555-1111
3. Fax line 999-555-2222 at a seperate location

Apparently their carrier will charge $150/month per line to move the lines to the new location so we've been tasked with coming up with a solution.
Also their carrier will not release the 1-866 number to any other carrier, so the Sales line must remain as is.


Currently what I've come up with is this:

1. Order a new landline at the new location
Hook up the new landline to Asterisk via an FXO card
Keep the Sales line (999-555-0000 + 1-800)
Forward all incoming calls to Sales to the new landline

2. Transfer the Support line 999-555-1111 to Vonage
Hook that up to Asterisk with an ATA & FXO card.


However I can see that this has problems:

1. All outgoing calls will tie up either line 1 or line 2
2. Vonage has unlimited US & Canada calling, so outgoing calls would be smart to originate from this line, however doing so would tie up the line.
3. I'm sure there are many other problems...


I've been thinking about DID nubmers and forwarding both the sales & tech support lines to the DID's, then use the new line & vonage for outgoing.

I know there are likely a million different ways to set this up, but I definately need some experienced direction. Maybe this can't be done... maybe it can be done better and/or easier.

Please.. if anyone has any suggestions please guide me through a good setup.

Thanks in advance!!!