Designing a dialog system?

<game>

<layout id='layout 104'>
	<interaction id='0' with='1'>
		<condition prerequisites='none' disqualifiers='boughtFarm'>	
			<speaker id='npc' pos='right'>Hello, welcome to the farm.\nThe place is a bit old.</speaker>
			<go to='menu' value='0' />
		</condition>
		<condition prerequisites='boughtFarm' items='farmDeed'>
			<speaker id='npc' pos='right'>Congratulations on your new- I mean, old farm.</speaker>
			<event action='createcondition' value='welcomeFarm' />
		</condition>
	</interaction>
	
	<menu id='0'>
		<item disqualifiers='dontMind' goto='1'>I don't mind.</item>
		<item disqualifiers='howOld' goto='2'>How old is it?</item>
		<item prerequisites='howOld' goto='3'>This place is too old.</item>
		<item prerequisites='howOld' goto='4'>A place with some history can be interesting.</item>
	</menu>	
	<menu id='1'>
		<item prerequisites='(money>=5000)' goto='5'>I would like to buy it.</item>
		<item goto='6'>I'll think about it.</item>
	</menu>
	
	<interaction id='1' with='1'>
		<speaker id='player' pos='left'>I don't mind.</speaker>
		<speaker id='npc' pos='right'>Great!\nWould you like to buy it?\nIt costs 5000 dollars.</speaker>
		<event action='createcondition' value='dontMind' />
		<go to='menu' value='1' />
	</interaction>
	
	<interaction id='2' with='1'>
		<speaker id='player' pos='left'>How old is it?</speaker>
		<speaker id='npc' pos='right'>It's about 100 years old.</speaker>
		<event action='createcondition' value='howOld' />
		<go to='menu' value='0' />
	</interaction>

	<interaction id='3' with='1'>
		<speaker id='player' pos='left'>This place is too old.</speaker>
		<speaker id='npc' pos='right'>Yeah, it requires a lot of work.</speaker>
	</interaction>
	
	<interaction id='4' with='1'>
		<speaker id='player' pos='left'>A place with some history can be interesting.</speaker>
		<speaker id='npc' pos='right'>Not much happened here.</speaker>
	</interaction>
	
	<interaction id='5' with='1'>
		<speaker id='player' pos='left'>I would like to buy it.</speaker>
		<speaker id='npc' pos='right'>Okay, that will be 5000 dollars.</speaker>
		<event action='giveMoney' value='5000' />
		<speaker id='npc' pos='right'>Thanks! Here's the deed to the farm.</speaker>
		<event action='getItem' value='farmDeed' />
	</interaction>
</layout>
[/code:2p3dc7aq]
Perhaps someone who has more insight into this sort of thing can lend me some tips/advice. I'm not sure if I like what I have.