This follows the rule of buy first, ask questions second.
Which means, you aren't likely to get the answers you want to hear.
I'm wondering what inspired you to make such a purchase without reading some of the reviews and asking questions first. It does seem that Nak owners are less than thrilled with the quality of this product...
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1064420201
And, while it would be a step up for a home theater in a box system or an entry level separates system, as a 7+ year old product, I'm not sure I would be anxious to go out and get it just because it has the Nak label on it. In fact, I might go the other direction altogether and aim to avoid it completely.
I do wish you luck with it, but it won't work with your Sony, and I would stick with the Sony.