Little Dorrit explained?

As I noticed I wasn't the only one confused about the ending of Little Dorrit, I thought I would have a look for a clearer explanation than the one the series gave us.

Here is part of the text from the book when Rigaud starts to read the will:

Rigaud snapped his fingers tauntingly in her face. ‘One thousand guineas to the little beauty you slowly hunted to death. One thousand guineas to the youngest daughter her patron might have at fifty, or (if he had none) brother’s youngest daughter, on her coming of age, “as the remembrance his disinterestedness may like best, of his protection of a friendless young orphan girl.” Two thousand guineas. What! You will never come to the money?’

‘That patron,’ she was vehemently proceeding, when he checked her.

‘Names! Call him Mr Frederick Dorrit. No more evasions.’

‘That Frederick Dorrit was the beginning of it all. If he had not been a player of music, and had not kept, in those days of his youth and prosperity, an idle house where singers, and players, and such-like children of Evil turned their backs on the Light and their faces to the Darkness, she might have remained in her lowly station, and might not have been raised out of it to be cast down. But, no. Satan entered into that Frederick Dorrit, and counselled him that he was a man of innocent and laudable tastes who did kind actions, and that here was a poor girl with a voice for singing music with. Then he is to have her taught. Then Arthur’s father, who has all along been secretly pining in the ways of virtuous ruggedness for those accursed snares which are called the Arts, becomes acquainted with her. And so, a graceless orphan, training to be a singing girl, carries it, by that Frederick Dorrit’s agency, against me, and I am humbled and deceived!—Not I, that is to say,’ she added quickly, as colour flushed into her face; ‘a greater than I. What am I?’

Jeremiah Flintwinch, who had been gradually screwing himself towards her, and who was now very near her elbow without her knowing it, made a specially wry face of objection when she said these words, and moreover twitched his gaiters, as if such pretensions were equivalent to little barbs in his legs.

‘Lastly,’ she continued, ‘for I am at the end of these things, and I will say no more of them, and you shall say no more of them, and all that remains will be to determine whether the knowledge of them can be kept among us who are here present; lastly, when I suppressed that paper, with the knowledge of Arthur’s father—’

‘But not with his consent, you know,’ said Mr Flintwinch."

Hope that helps!

Web link: http://www.bibliomania.com/0/0/19/39/frameset.html