DD1 has poo "issues"

Lately she has been complaining when pooing, and a couple of times I have had to help her work the poo out cos its been so big its hard for her to get out on her own accord (yes, its just as disgusting as you would imagine!!)

The other day she was at the table and in complete hysterics about doing a poo, I had no idea what was going on with her, she was making such a fuss. However, when I checked her nappy (when she would let me!!) the poo was massive, and as hard as concrete, and her bum had a little lump under it, sorta like she pushed too hard or something, and it damaged it.

So anyway, we took her to the doc the next day, he said that there wasn't any lump so it must of gone away, but referred her for an xray on her tummy.

Results back from the xray - she has a build up of poo in her system, he says there is about a kilo worth of poo stuck in her, blocked up to her intestines.

So we have to get this crap outta her! I've been pumping her full of prunes, prune juice etc in an effort to get it started naturally (the doc wanted us to try this for 3 days before going to medicine to get it to move cos it causes tummy cramps and he didn't want her in any more discomfort) but nothing is moving at the station as yet.

Any suggestions on other natural things to try? not that I'm wanting to deal with a kg of poop any time soon... and I think when it starts I'll be switching to disposables for a while!!!! lol

Any help would be awesome.