I'm astonished at the posts suggesting that because someone wants to see her mother who she seems to love in preference to her MIL who she has told us is 'blunt' (I think this is probably code for 'rude and unhelpful') she is somehow being an ungrateful selfish person, who can't be arsed to put herself out (for someone who she doesn't like much anyway)!
FWIW, I had got on reasonably well with my MIL before the birth of my daughter. As soon as my daughter arrived, I hated her. I didn't hate her because she wasn't my mum. I hated her because she was pushy and unhelpful and full of self-centred martyrdom (oh look, I'm doing the washing up, how kind I am - FFS, WE HAVE A DISHWASHER).
My parents in law came to see us in the hospital and they came to see us on the day we came home and they came and they came and they wouldn't bloody go away. When they held my daughter in a way that made her cry, they wouldn't listen to me when I told them why she was crying. When they brought lunch, they just ate it and couldn't be arsed to put their plates in the dishwasher (nobody was expecting them to do actual housework). When they came, they wanted to hold my daughter constantly while I made tea and stacked the dishwasher. While I see that they loved her and wanted to be close to her, I am her mother and it was a hundred times more important for me to hold her than anyone else in the world. In the end, we just told everyone to bugger off and leave us to it.
If your parents in law are nice, sensitive, kind people, by all means have them round however often they want to come. However, if they're a PITA, tell them to stay away until you are ready. One week won't be the end of the world and it might make you feel a lot better as by then you will be much more confident as a mother and able to stick up for yourself a bit more.
I find all the mothers of sons (Abbey in particular) worrying about how they'll never get to see their grandchildren a bit weird. All you have to do is be nice to your DIL, surely? Behave like a normal person, bring food, make your own tea, tidy up after yourself, offer advice only if asked etc etc etc. And, er, just accept that most women are more likely to want to see their mothers than their MILs at this time, unless their own mothers are a nightmare of course.
By the time my daughter was 7 months old, PILs were constantly whinging about 'can't she have a little sugar on her fruit' etc. I really dislike them both. They don't listen to me and, more importantly, they don't listen to my daughter. Their behaviour after her birth definitely heralded what was to come!