I had the very same dilemma, for me my most uncomfortable time to carry is in the car. I'm a big guy so there isn't a lot of room for a gun to fit, also not a lot of room makes it VERY hard to draw if I ever needed to. So i have done a lot of research on this and have found there are actually quite a few options out there. The holster that SSGN_Doc posted is actually a holster sold by the NRA so if you go to the NRA-store online you can find that holster. My only concern would be if that panel in the civic is strong enough to support that much weight (you can always reinforce it). The NRA store has one other option I believe that attaches to your seat belt.
I found another site with designs I like so much more! The web site is: http://www.texascustomholsters.com/
They have lots of pictures if you scroll to the bottom of that first page.
I like this design the most
But my main carry gun is a model by beretta that is no longer made and NO one makes anything for so I decided to make my own out of kydex but it will be similar to the picture I attached. If that interests you to make your own let me know and I can show you where and how to get started with kydex.
If you can't take your gun into work with you personally I wouldn't leave it just in a holster in my car I just don't feel comfortable doing that my self. So what I did is I went on amazon and I found a little lock box that just fits 1 gun and it has a steal cable you can attach to your seat base. You can get a 3number combo or a key lock. I'm sure someone could still get it if they really wanted but I'm sure it would slow them up.
I hope all this helps let me know if you have questions and good luck!