Your next step is to make an offer.

I get the impression from your post that you don't have the money to make an offer. It also seems you don't have the means to make the movie. So I think, you're right. You're going to have to find a producer or prdoCo who will put up all the money to make this movie.

This will put you in a difficult position. The company (or producer) will be putting up the money to buy the film rights to the book, they will own the rights - not you. Since the rights are available, the first person (or company) that makes an acceptable offer will get those rights. If you approach a producer or prodCo you will need to - somehow - position yourself into a position of importance. A position in which you stay connected to the project even though you don't own the rights. How; I have no Idea.

If you have the means to take out a big enough loan to buy the rights, that puts you in the position you want to be in - the owner of the film rights to the book. then you can go to an interested producer or prodCo for production money.

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The aim of an argument or discussion should not be victory, but progress.
Joseph Joubert, essayist (1754-1824)

Thanks a lot for your advice.

How much would you say I am looking to borrow in a loan?

?There is a fine line between censorship and good taste and moral responsibility.?
- Steven Spielberg

How much are you going to offer to buy the film rights?