Current daily rates for tuk tuks are $15-18. An a/c cr (Toyota camry) is $30. Your driver will take you round the temples, wait for you to finish with one and take you on to the next one - they are not guides and are not allowed to accompany their passengers into the temples. If you want a guide your hotel can sort that too - you're looking at around $30/day. Temple pass costs are $20/1 day, $40/3 days - free for kids under 12.
A 3 day trip you can see the highlights and probably fit in a visit to one of the lake communities - stay away from Chong Kneas (it's just scams-ville) Water levels will impact on this - when are you planning on visiting?
Agree with Jim - just book plane tix and hotel - the rest you can do through the hotel when you arrive.
