I think that for now you can wait until the rate drops a little, and then buy. If the rate drops to, for example, 55 thousand dollars, then you can buy. As for the cryptocurrency exchanger, I can recommend https://letsexchange.io/exchange/mkr-to-btc . There you don't even need to open an account, and you can do everything without registration. Just go to the site, choose a cryptocurrency pair, and enter the amount you want to exchange. You will figure it out there yourself.