I’ve had a lot of dogs in my life. Every single one peed in the house when I first got them - I expected it. They need time to adjust to you and their new surroundings. Also, cockers are a little nervous to begin with (and prone to ear problems, so clean them regularly. Trust me…I have an akita with major ear problems - you don’t want that.)
The first thing you should do is take her to a vet, so you can check to make sure there are no medical problems, like a urinary tract infection. Try to bring a urine sample with you to the vet - he/she will likely request one. A pie tin works well with a female dog. Crimp a little spout on the edge first, so you can pour some into a jar or film cannister.
After that, what you need to do (if you aren’t already doing so) is work in two areas: outside time, and some discipline (by that I mean having Peaches obey commands).
Until she is housebroken, you should only take Peaches outside to do her thing. No outside play time, no exploring for now. She needs to know that when she goes outside, it’s bathroom time. Whenever she goes, you should praise her like she just did the greatest thing in the world! Take her back inside afterwards. Eventually, she will associate that peeing outside = happy person.
You’ll need to let Peaches out every few hours when someone is home. This is so you can give her as many chances as possible to go outside, so you can praise her for doing good. Even though she now holds it while you’re home (and awake), this will help her learn that she is not to go in the house. You probably already know this from other dogs, but when you play with a dog, or company comes by, they get excited and need to go out right away, especially a new or young dog.
You probably wouldn’t need to crate her during the day when someone is home, but you should crate her at night. I’ve never had to crate my dogs, but I know that they usually like to hole up someplace when they need to feel secure, like during a thunderstorm. Most dogs view their crates as a den, as a safe haven. The worst thing anyone can do is punish a dog and then put it in a crate. Make that crate a fun place - play with her inside, maybe put a blanket over it so it becomes her little hidey-hole. The crate should only be big enough for her to stand up and turn around in, and lay comfortably. She will learn to enjoy being in the crate, and won’t mind when you close the door at night.
Like Bookworm said, she may eventually learn from Jimmy to let you know when she needs to go out. I have a friend who mounted a little refrigerator wind-chime type magnet by the back door. Every time the dog went out, he jingled the chimes (any type of bell, etc., would work. Just like Pavlov.) He then started taking the dog’s paw and tapping the chimes before letting him out. Now, the dog lets him know when it’s time to go out. It took a while, but it’s something you might want to try, though you probably wouldn’t hear it while you’re asleep. We don’t wear shoes in the house, so my dogs associate putting on shoes with going outside. My youngest dog will come up to me when he needs to go out, and then just look at my feet. Jimmy whines. They’re all different - you just need to learn Peaches’ signal.
Also, with any dog, work on some commands. Most dogs were bred to do some type of work, and they naturally want to please you. A bored dog is a destructive dog. Start with one command at a time, and work her up to 5 or 6. You only need to spend 10-20 minutes a day (but only work with a dog when you’re in a good mood). By doing this, you will build confidence in Peaches, and thus help her to adjust to her new surroundings.
The most important thing to remember is that she will probably still have some accidents at first. Just deal with them, and don’t punish her, or else you’ll undo all the work you’ve done until now. With patience, she should become fully housebroken in about 2 weeks.
Good luck!