
Toilet training pups takes a lot of time and patience :)
When you take her outside you should be encouraging her to go. Use a word that she will come to associate with toilet, like "hurry up", "be quick" etc. Whilst she is going use the word. The minute that she has finished make a huge fuss of her and give her a treat or a toy, basically whatever she enjoys as a treat. You need to go back to basics, treating her as if she were an 8 week old pup.
Please bear in mind that she is still young at six months and you say that you have just got her, she will take time to settle in and become used to you and what she deems to be strange surroundings.
Also, did you speak to the previous people about the diet that they used to feed her? In my opinion, she is too young to only be eating once a day. I would say at least twice a day. My pup is 6 months old, admittedly a larger breed than yours, but she is still eating 3 times a day plus, because she is growing rapidly and also always hungry :)
And finally, have you taken her to the vet for a check up to make sure that she is healthy, wormed etc? You can also discuss any concerns that you may have at the same time :)
HTH