Some advice on a Carl Zeiss 4,8/180 mm Sonnar Lens

[trm382]

Hey guys, I'm a first time poster and I have a question that maybe someone here can help with.

So my girlfriend was left her grandfather's camera lenses when he passed away and we just recently started looking at them. One of them is a Carl Zeiss 4,8/180 mm Sonnar.
Here are a couple pictures of the lens (taken in a hurry with my crappy phone camera, sorry about that):
https://www.dropbox.com/s/z0ag82yt3sguu4m/IMG_20130819_190233.jpg
https://www.dropbox.com/s/x1kiujjxgxhrdvf/IMG_20130819_190256.jpg
I found a similar one on ebay here:
Carl Zeiss F Linhof 4 8 180 MM Sonnar | eBay
What I want to know is what's a realistic price and where should I take it to be checked out and sold properly. If it's a really nice lens I want it to be getting used and although we have a DSLR that we use as amateurs, I don't think we need this much lens. Can someone help me figure out what we have?

Edit: I emailed B&H in NYC and they said that it's a Pentacon Camera lens and those cameras haven't been made in 35 years.
They suggested trying to sell it on ebay.
I did do a preliminary amazon search and they apparently make adapters for pentacon lenses to modern nikon/Canon cameras.
Here's a search: Amazon.com: pentacon lens
Anyone have any additional info? I'm looking for details so when I post it I can describe it accurately.

Edit 2: I'm definitely missing the mount, here's a picture:

https://www.dropbox.com/s/ctl8gj5p5iprlbc/IMG_20130826_192356.jpg

Edit 3: I emailed the Carl Zeiss company and they responded! Here's what they wrote:

Thank you for your inquiry to ZEISS.

Those lenses for Linhof large format cameras were manufactured after 1954, further details about the manufacturing date are not available.
"Kadlubek´s Lens Catalogue (2009)" lists this lens type for 630 US$ (in mint condition).


Sincerely,
Bertram Hoenlinger