Translated.

According to the author's blog this is a "stational joke", so I suppose バインバイン is a joke on Valentine (http://wave.ap.teacup.com/caffeinism/102.html).

Also, I know the literal translation of "知るか！" would be more on the line of "Why should I know (that)!", but I couldn't think of a shorter translation.

"As if I knew!" is a close literal English equivalent. "Hell if I know!" would be probably more likely to be actually used in such a context, but is less close. I took the liberty to apply the former.

Thanks 葉月! As Oe Kintarou would put it, 勉強になりました!