You sound like a great student. My best advice would be to attend any "Open House" events that hospitals have for new graduates with your resume in hand. These events are notorious for giving out interviews on the spot where I am from. Are you from a big city? You might want to decide applying/moving to a big city so your options are bigger. I'm from a big city so many hospitals had open ED spots available reserved for New Grad RN residencies.
As for being upset about OB, it's ok. Me (and many of my guy friends) were upset to be placed in Medsurge for our Capstone because we all wanted ED. I know how you feel. At the end of the day, all that matters is that you are a great student nurse wherever you are placed because your preceptor/manager will be a good Letter of Rec. During your lunch period at your capstone, maybe stop by the Managers office and mention if that hospital is having any openings in the ED. Again, make sure you are coming to clinical everyday with a good attitude because people will notice...and talk. Again, I cannot stress this enough...wherever you end up...just have a good attitude, you never know when you might need someone's help.
Lastly, there is a guy who works in the ER that has a popular youtube channel, "Kaynen Brown". He has some good tips for Soon to be Grads trying to work in the ED. Goodluck!