how big is the factory radio opening? from the pic it looks like it's 1.5-DIN (7" x 3").
but I've seen a few worklogs where people managed to squeeze a 7" screen behind it (I don't know if the bezel cuts off a bit from each edge). you could do what others have done and mount a 7" panel to the factory bezel. if you run the carputer without a head unit then that would be fine.
the easiest (and cheesiest) solution would be to get a trim kit and mount a single-DIN motorized flip-out monitor where your factory head unit is. there is/was a company that makes half-DIN flip-out monitors (don't remember where I saw it). that would probably fit above your alpine.
you have plenty of options depending on how much modding/fabrication you're willing to do.
I've attached a few GIMP'ed images of your [potentially modified] dash to give you some ideas of what you could do if you were willing to spend the time and effort.
[image #1] is a more extreme option which involves re-routing your dash vents (to the floor?) and mod/fab your dash panel and radio bezel to accommodate a 7" or 8" monitor
and a head unit.
[image #2] involves mounting your head unit (or just the faceplate) where the ashtray and cig lighter are.
[image #3] is basically the same as #2, but involves moving the HVAC controls down. this keeps the audio/video in the same spot.
