A good thing to try is to praise her when she pees outside and give a treat or favorite toy right away. Bring her back inside, and then take her right back out again. She may pee again, and if she does, praise and treat immediately. Bring her back in, and go back out again right away.
Another thing to do is attach Tilda to you when you bring her back inside. That way you can keep an eye on her at all times, and when she is showing signs like she needs to poop, take her outside immediately! If she poops outside, PRAISE AND TREAT like there is no tomorrow!
Some dogs need extra guidance when it comes to housetraining, and many times you have to start all over again. Tethering her to to with a short leash around your belt loops is always a good way to work on housetraining skills.
Another thing you can do is crate her right away when you bring her back in. Most dogs do not want to soil in their crate. Crate her for a few minutes, then take her back outside again.
Does she give you an indication that she has to potty? Does she circle around, whine, paw at you, etc.? Once you learn her signals, subtle as they may be, you will get it figured out. It just takes time and patience.