Is the Commodore 64 a uC or is it a computer with an OS ? (I don't know so I' asking)
Does it have more memory than an arduino ? Can it run Excel (I haven't seen anyone do that with an arduino. So far I have not heard anyone mention csv files which are probably something an arduino could deal with and while it is not an "Excel" file perse
the Excel file in question could be converted to CSV prior to the using the arduino to extract the information. At least it doesn't sound as far fetched as the OP's question.