Hi there and welcome to Electronics Point
Yes, myself can direct yourself to two good sources of electronic components: Digi-Key (
http://www.digikey.com) and Mouser (
http://www.mouser.com). They have the largest range of components. They are both based in the U.S. and their overseas shipping rates can be high. If you tell us your location (better yet, put it in your profile - there's a place for it), we may be able to suggest some local suppliers.
The original displays for that unit is are Toshiba TLR312 common cathode units, but they're no longer available. A suitable equivalent probably exists, and I will dig it up for you if it turns out that the display is actually faulty. But I think it's more likely that there's a problem elsewhere - a broken track, a broken resistor, or possibly a faulty driver IC (the one marked MSM561 located beside that display).
Each TLR312 has five pins along the left edge, and five along the right. Here are the segments and pin connections:

You can zoom in on the picture by clicking it.
From your description, it sounds like segment C is out. That corresponds to pin 6, which is the bottom right pin, closest to the decimal point. That's the pin you need to check carefully. Follow the track through the resistor to the MSM561 driver IC and check for visible damage. If you have a multimeter with a continuity test function, use that to check the tracks. Flex the board gently as you test; it may be a very thin crack. If you don't find anything, let me know and I'll advise you further.