1- These butterfly and wisps I collected, what r they for?

2-Mountain flowers can be used for a reliable potion?

3-What are the mixage of healing potions? what are the ingredients of a restore health potion? are there any other combinations?

1 butterflies and wisps can be made into potions. You can use the orange butterflies for restore health, and blue for fortify conjuration. (And more)

2 yes, mountain flowers can be used for reliable potions

3 Orange butterfly wings, Blue Mountain flower, Blisterwort, wheat (and more)

For 3

I use only ImpStool+Wheat combination, Is there any more for my level?(15 character level, 23 Alchemy)

Have a lookie at http://www.uesp.net/wiki/Skyrim:Ingredients

You can experiment at any alchemy table, just mixing ingredients together to learn. It's not level dependent, though you will get more effective potions as your skill grows, and that only happens by doing it a lot.