A little situation here...my wife's grades in undergrad in maths were not that great (C to B+) but her quant score in GMAT is 51 and she has been a Maths Olympiad person and all that so her maths is actually pretty good... So should she actually leave it to the AdCom to decipher this fact or maybe perhaps an optional essay is in the making ???
Do help out guys....
I had low math grades (in one or two cases even lower than those you list) and a lower GMAT quant score than what you list.... I wouldn't sweat her situation at all.