Females are, as a rule, easier to train. I'm surprised your male hasn't 'shown her the ropes.' Usually if you have another dog that is house trained, the newcomer - especially if it's a puppy - learns from the older one.
This is not happening - possibly because: if he is an 'in-tact' male, she could be in heat & he's bothering her (the smaller breeds generally begin their first heat cycle between 4 & 6 months & about every 6 months thereafter). If you ahve not already done so, I encourage you to please have them both spayed/neutered immediately. They will make much better pets, live longer & be healthier: no prostate cancer or mammory cancer, no marking.
Marking: if your male hasn't already, he might start marking where she has peed...he may already be doing that without your knowledge...AND females mark too - sometimes even hiking their leg like the males. In fact, THAT may be why she's peeing in the house - females tend to be the 'alpha' in a household of more than one dog; So if she smells where she's gone inside, she might think it's acceptable. (Unfortunately, shampooing carpets do NOT get rid of the odor. YOU may not smell it, but it seeps into the pad & onto the wood/cement below & they can still smell it. You may have to move a piece of furniture over the spots - if feasible - in order to make sure those spots are not accessible to her).
You probably need to put her in a crate if you're not playing with her or training her or if you can't watch her every second. Get her out every few hours - (I usually sayd, 'let's go potty' or something, but no petting or playing or anything ....strictly business. Carry her outside to the place where you want her to potty, put her down and say, 'go potty' or whatever word you want to use. You may need to put a leash on her if she's going to try to run around and play instead of taking care of business. After she finishes, praise her, give her treats, etc and take her back inside. Spend some time with her,playing or training, etc. But again, if somebody is not going to be able to watch her, put her in her crate.
Your children are old enough to help with this so it would be GREAT to get the whole family involved. But BE CONSISTENT - you all MUST use the same routine and words!
THIS IS CRITICAL: Do NOT put any food/water/towels, blankets, cushions/piddle pads/toys - NOTHING in the crate with her. And put the crate someplace where she's out of the 'main path' .... bedroom, utility room, etc..... it shouldn't take long for her to get the idea.
If she has to be alone during the day while you are gone, the crating is invaluable. She should be able to go for about as many hours as she is months old - IF you don't leave food/water.
If you will be gone more than 4 or 5 hours, you might want to get a baby gate and confine her to a tiled area. You can put newspapers down (mine would never use piddle pads), in the area with her - still no food or water. Remember, she goes all night without food/water, it won't hurt her to go without during the day. It would be good to get her on a timed feeding schdule - at least 2 meals a day. Leave the dog food down for about 30 minutes. If she hasn't eaten, pick it up - no more until the next meal. No treats or snacks.
The main thing to remember is she is like a baby ... they generally go to the bathroom after waking up, after a meal and after playing. AND, at 5 months old - she's really like a baby. Playing is fun, but she needs lots of sleep too. That's why she needs a place away from the activities of the household. Dogs are 'den' animals - they seek out 'cave' like places to rest when they're tired or scared. She will grow to love her crate & once she is house trained, you will be able to leave the door open & if you miss her, she'll most likely be in there sleeping.
Good luck with your little ones!