Fatman iTube Carbon or an A/V receiver for audio

Hello, new to these forums.

I recently purchased a Fatman Itube Carbon ( http://www.fat-man.co.uk/docs/product_07/iTube_ValveDock_Carbon_Edition_2.shtml ) and picked up a set of Infinity P162 speakers. The system does what it says and sounds quite decent for small room listening. Overall a nice system but after reading through some forums, i feel as though i could get more for my money (550-600). For instance, I am somewhat disappointed in the lack of inputs and outputs: 2 rca inputs, one 1/8 input, no digital inputs. S video output that only works with videos that you have on your ipod (i've yet to get this to work properly). No headphone out!

My original intentions in purchasing the system was to have a quality listening setup for my rather "cozy (13 ' 17)" condo living room. I was planning to use lossless files on my laptop tied in with airport express. The itube doesn't have a digital input and i have recently read horrid reviews about the analog out on the airport express.

So therefore, if i wanted quality sound from the system, i'd have to leave my iphone docked...which can be such a nuisance.

To make a long story short... I'm very confused at the moment as to what to do about the system. My current needs are mainly to have a quality 2 channel setup for my living room with the possibility of future expansion. I have limited experience with audio equipment. In fact, I was not aware that A/V receivers could be used for a 2 channel setup. I have a few questions and would greatly appreciate any help.

1. Will a receiver like the Denon AVR-2308CI provide me with similar or better listening experiences when compared with a valve amp such as the Fatman iTube

2. How would you setup the receiver so that all the power is dedicated to the 2 channel system (with a subwoofer)

3. Would the receiver appropriately drive a high impedance set of headphones such as the HD580s 300 ohm

4. Please recommend a quality receiver used or new in the 400-500 price range.