I am assuming that the airprot you refer to is Las Americas?? If this is the case, a cab should run you around $25.
Am not familiar with the mini market.
Weather...hhm, only G-d can answer that! Seriosuly all jokes aside, do yourself a favor and dont look at the weather forecast prior to your trip. Your arrival does co-incide with the onset of "Hurricane season" and it may be rainy or cloudy but in my vast experience in the DR and Juan Dolio specifically, the sun will shine too. Hope for the best and make the most of your time there no matter what the weather!
