If you are staying an entire week, renting a condo is the way to go. One bedroom oceanfront places are cheap, no one wants a one bedroom at what is mostly a family area.
google "north myrtle beach condo" or "north myrtle beach condo rental" and go with whomever comes up with a good deal I have never had a bad experience.
I have also hit VRBO.com and found some good deals there, you are not too late to book for next month.
If you are only going to be there a couple days, I stayed at this place once
it was nice enough