Wiring Problem - USB powered Speakers

[#1]

I have a small MP4 player, about the size of a mobile phone.... I use it for music vids in the car, when I am waiting for  `er indoors, to do the shopping.  At the moment, it is linked up to a pair of battery powered amplified speakers, which last for about a week or so... ( cheap £1.20 for 16 AAA batteries) ( I do have rechargables, but use them on other things)..
Bought a pair of speakers from ASDA today, which are quoted as "USB Powered"... and bought them to compliment my new 10" laptop, (see other threads in Windows Software)
then I thought... it would be nice if I could get the MP4 player to use these speakers.....
MP4 player has the normal 3.5 stereo out for phones, and also a "mini usb" socket  (same as on a camera) for loading up stuff via a USB lead, and its treated as a external hdd when plugged into the laptop for transfer of files....
so... Can anyone advise me, ..... A... could I use the "mini" usb socket, to drive the speakers. ?
B. could I use the 3.5 stereo out to drive the speakers?  (EDIT EDIT.... just got them out of the box,... there is a USB lead and a 3.5 phones jack.... so will only nee the answer to A above... !.... ( and also the wiring queries below).... 
There appears to be 4 connections on a USB socket/plug  so if either or both of the above could be utilised. what would be the profile of the wires connecting ?
Am guessing one would be "common" ...... one would be Right channel..... one would be left channel, and the last one, would be "power".... Is there a "wiring diagram" somewhere that I could use to identify the wires, and make up my own connection lead?

[#2]

If you have a car FM radio you could use one of these plugged into the player.

[#3]

My car radio only works when I pull it right out of the dash, and the lead wires are at full stretch.!... seems to be a "speaker" wiring problem, but it could be anywhere from the socket back to the speakers, and I`m not that bothered with the radio anyway... !... so I`m not going to spend hours trying to trace the fault...

[#4]

use something like this and power both your speakers and MPx player.

[#5]

Hmm... Now that might just do the job... Thanks... ( the AAA battery amplifier, actually uses a USB connection to the MP4 player, so worth investigation... 

[#6]

I hae this one: http://www.ebay.co.uk/itm/GRIFFIN-TWIN-DOUBLE-USB-CAR-CHARGER-IPHONE-IPOD-BLACKBERRY-PHONE-HTC-SAMSU... (though I paid a lot more), it fits flush with the lighter socket in my car so I can still close the hinged cover without removing it - works well for charging phone and satnav at the same time.

[#7]

@w23.....  Thanks for that.... did see one from HongKong.... @ £1.55  (inc p&p) !.... but thought better of it !, have ordered the one you linked to... 

[#8]

Hope it's a good 'un (mine certainly is - well over 2 years use with no trouble).

[#9]

I`ll try to remember to let you all know.... not due until 12th.....