**Adding This:
many kids just HATE high-chairs... and will not eat strapped into one. Both my kids were like that. I fed them, at a child height table... or the coffee table. Maybe she will eat if not jailed into a high-chair???
How old is your baby?
Next, well my kids were breast hounds. LOL
But what I did, was introduce the sippy-cups from about 6 months old.
What I did was not only bring it out at feedings/'meal' time... but, I had several sippy cups out and about, putting them out on the coffee table, places where they played... or on the floor if she is not yet sitting/standing. And, even in their crib too... And I put water in it. The point being... for the baby to get used to seeing it, and even playing with it... and picking it up... all in a child friendly way. Not making it a "have to" only at the dinner table etc.
Kids also like to be able to grab things at their height & explore... thus, I put them out on the coffee table, their kiddie table or on the floor etc. It makes it more approachable.
Then, my kids did use it and drink from it.. Because then it was not a "battle" nor a my "making" them do it. But it was just more child friendly.
And maybe your baby is just not ready for a sippy sup. Or try a straw cup.
And you said she is not really eating gerber baby food/solids... so maybe she is just not ready.
Again, how old is she????? That makes a big difference.
All the best,
Susan