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I presume you have travelled by now and can probably answer this question yourself! But for those that may want to travel to Botswana (my favourite country in Africa!) in future:
Botswana readily accepts visa and master cards, notify your bank that you will be using the card in a foreign country, with dates. I've travelled extensively in Botswana (and lived there for a while) and never had a problem with my South African bank card being accepted anywhere in Botswana - I have a Visa card, and carry my Mastercard as a backup. The only country so far where the ATM would only accept Mastercard, was Malawi.
Most lodges and large shops readily accept your credit card as payment, it does however happen that the power is off or that the internet reception is poor, or maybe "the machine is broken" - so I always carry enough cash to pay for a tank of fuel, or my shopping (about P2000= about US$200). You can easily withdraw Pula at the ATMS, or if you bring dollars in cash, can exchange this at most forex bureaus. Cards that are not readily accepted is American Express and Diners club.
Hope that helps for future travels to Botswana!