Oh no, I can see why none of her friends volunteered to step up! Perhaps they already knew what she'd be like! She is only thinking of herself and the gifts she wants to get.
I'm guessing the shower isn't for a few weeks? If possible return some of the decorations, favors, gifts, etc. Things that are still in their packages can go back to the store. No need to go in the hole for her baby shower!
Is it at a hall? A person's house?
Instead of expensive food, get sandwiches and appetizers. Instead of expensive drinks, make punch. Instead of expensive favors, get dinner mints and wrap them in tulle and add a cute little tag. Instead of expensive decorations, get a little confetti for each table and use the dinner mints in tulle as the table decorations. Maybe purchase a congratulations sign--that's it!
Don't buy her a gift, the shower is her gift.
If she continues to say "Oh man, I really need presents" stop joking. Say seriously "What makes you say such a selfish thing?" If she gets mad, oh well!
I've noticed this trend a lot lately, bridezillas, baby-zillas, not-so-sweet 16s all hungering for gifts, not time with friends and family. What a sad culture we've become.
This girl is not a friend, a true friend would not be so selfish. So do your best with what you have. No need to go overboard! And if you can, enlist the help of some of her friends. When you ask say "I'm having a hard time, would you mind helping with the cake in lieu of a gift?" or something similar. This girl doesn't need baby shower, she needs a cold shower so she can wake up!