helping 3 yr old to say hard g and c

[LACh1]

Hi, my little girl just turned three on sept 20 and is currently going to speech and is making steady progress.  However i am not very happy with the help we are getting as we don't seem to be getting many activities to do at home.  She is having difficulties making the hard  g and c sound and i am out of ideas as to how to help her.  I have cut out pictures with these sounds and tried to help her say them, taught her songs with these sounds in them and read books with them as well, however as she can't make the sounds she sings the songs and says the words with a d or t sound instead.  I have tried to show her with a mirror where her tounge should be in her mouth but she can't seem to do it, also used a tougne depresser to try and keep her tounge down while making the g sound but with little success. Any ideas or advice would be great as i am all out.