conmankiller: BadCreditGuy - It is highly probable that Cap 1 will charge you for going over the limit even for One day, irrespective of what has caused the problem, their transactions are computerised there is no Human factor......however, should they levy this charge, get straight onto them and protest that it was a first offence (if that is the case) explain it will not occur ever again and politely ask them to refund any charge.(no promises, but worth a try)
I couldn't find Capital One T&Cs online, but FWIW I looked at my MBNA T&Cs. There is an interesting clause which permits MBNA to decline a transaction which would cause yet to be applied charges, including interest, to exceed the credit limit. In the case that MBNA chose not to invoke that clause I would not expect MBNA to penalise a transaction within the credit limit, other than remedying the situation through the next minimum payment. I haven't gone further and looked for a clause which deals with the OPs predicament.
Anyway, as I've studiously maintained, only the Capital One T&Cs are relevant to the OP.