It is not a matter of it being supported in LMCE, but of it being supported my Linux itself (and mythtv). So unless you have the skillset to help out with the linux kernel drivers, you have two choices:
1) wait for it to be supported.
2) use something else
option 2 is your best bet, since option 1 is likely going to take quite some time yet. so yes, the 2250 might be the "perfect" card for your setup, but if you want this to work you may have to compromise a bit. First, figure out exactly how many of each tuner type you need now, and in what way those numbers may change in the future. Then find and purchase hardware based on your needs. Keep in mind that there is no supported one-card solution right now.
Your best option for ATSC digital tuners is the Silicondust HDHomeRun. It is network attached so it doesnt take up a slot in the computer, and brings two tuners to the party.
You best option for analog is the hauppauge PVR-x50 and PVR-500 (if you can find them, they have been out of production for awhile) if you have spare pci slots, and maybe the Hauppauge PVR-USB2 (i have no direct experience with this, and it may also be out of production).
In any case, make sure to review the wiki page for tuner cards, that will give you some ideas of what the possibilities are.http://wiki.linuxmce.org/index.php/Category:TV_Cards