Cam tension gone/collapsed on Rover 200 1100cc?

Is it possible to do a self-repair on the car in question? If popssible what do I need, and how do I fix it. Are there any online manuals that I can follow, whilst repairing? What does it mean if the valves are bent and what actually are they?
The Breakdown Recovery service RAC, in UK, informed me after inspection of my vehicle, That the cam tension/housing has collapsed. there is no damage to the cogs, but the belt is gone.
When looking at the cam with the cover off, below the main cog is an aperture where a metal tube is resting on the aperture lip. The recovery guy said that, there should be bearings supporting this, and I am looking at just over £100=$200 approx. When calling various repair shops, (Respectable), they are quoting nearer to: £500=$1000 approx.
The car is only worth £500-700: Please, what do I do? Is it worth buying an engine from scrap yard and switching them over?
ALL responses of valid nature will be gratefully received.
Thanks
Ed