Coolant in oil

That is not a lot of coolant, but you will want to have the oil changed soon. Antifreeze melts the soft first layer of metal on the engine bearings. Those bearings are thin curved strips of metal that have very highly-polished rotating parts on them. They have a clearance of around.005" that is filled with pressurized oil. When the metal starts to come apart, the flakes chew up those polished parts, and that further destroys the bearings. That can cause a major failure within minutes. You want to get that antifreeze out of there as soon as possible. Be aware too that during an oil change, there is about two quarts of oil that does not drain out. It is stuck in the oil pump and passages. That means there will still be a little antifreeze left in there after one oil change. The amount you described is rather small, so I would be comfortable that just one oil change will get most of the antifreeze out.