How do i buy Bitcoin on this exchange to pay for fees ?
You buy Bitcoin at an exchange like Poloniex and send it to your counterwallet address.
(There is a possibility to exchange XCP for BTC at counterwallet but it needs some manual console command BTCpay which I don’t know)
Bitcoin fees are currently low so you can send transaction at 1 sat/byte = 0.000025 btc = $0.25 for a small 250 byte transaction.