I'm a bit confused - are you asking how to start mixed feeding or are you asking if you have to give formula if drinking alcohol?
Alcohol only goes through to milk in very tiny amounts so don't worry about it, obviously if you're planning on drinking 3 bottles that might be a concern, although about your health as much as anything!
You don't have to "pump and dump" or give formula if you want to drink.
If you want to mixed feed then it's best to get breastfeeding established first and then introduce bottles slowly so you don't disrupt your milk supply.
Oh hang on, are you asking if mixed feeding is a good remedy for sore boobs? If so no, you want to remove the milk so feeding directly is best. It's only sore for the first day or so when the milk comes in, should be much more comfortable after that. Just feed on demand, don't pump or express and it will be fine.