Engines for a dead Discovery

Hi all,
A couple of months ago I bought a Landrover Discovery V8i for £500 for a roadtrip between London and Barcelona (for the Barcelona GP). Needless to say it blew up somewhere in the middle of France! Anyhow, after spending the best 50 quid ever with the AA, I now have my Landy back here in the UK.

My questions to you guys are:
1. How easy is it to get a cheap replacement 3.9 V8 engine?
2. Do I have to get the same type of engine again? Could I place a diesel engine in instead?

Please excuse my ignorance here, as you can tell, I won't be doing the work.

Cheers,

]y,d be better off breakin it an puttin cash with wot y were goin to spunk on an enjin an gerrin a tdi, well cheap these days.

2.8 Isuzu turbo diesel.

Way to go.