You should have it within a week or two. But I think you should have waited for the unconditional letter to be added to your visa package. It's all good, though.I have applied for 2018 fall undergraduate intake. I have received the conditional offer letter and I've also used that for my visa application. i have also completed all the requirements asked by them. How long will it take to get the unconditional, final offer letter?
Cheers!
Liquid