Roll20 has dice roller on screen and in the chat window. /roll 1d20+2 or whatever. You can create macros in the gear of the Roll20 controls. it's a little more complicated though. Someone in the game can help you. Enjoy :-)
Had our company Christmas party here and just have to say that this place is amazing. The food was some of the best food I have ever eaten in a public restaurant. The chef is amazingly talented and provides a dining experience you will never forget. 5 stars plus.