Man, I think I might be getting a bit obsessive, because I just tried to see if I can manipulate the image into showing whatever characters are being concealed behind the glare. This is the result of considerable sharpening in IrfanVeiw.
What I could tell so far is that obscured part of the top row reads "特大ワイド", meaning "extra-large wide". The bottom row is obviously Cheer-chan's name, given the clear hiragana for "Chia", but I can't tell what the kanji are.
Courtesy of kittey, we now have a slightly clearer version of the cropped image here. I'm almost certain that the second kanji is supposed to be 足. The first one is still vague, but kinda looks like 安; don't take my word for it, though.
That being said, the only Japanese surname I could find that would correspond to 安足 is "Yasuashi".
You know, I'd ask Himura-sensei himself about this if I knew how to write the question coherently in Japanese.
After talking with Moonspeaker, we've eventually concluded that the most probable candidate for the partially obscured kanji forming Cheer-chan's apparent surname is 安堂, which seems to be an existent family name that can be read as either "Andou" or "Yasudou". I'm going with the former since it sounds better.
