Q1: I suggest to purchase a new motherboard because yes to reach the speed of 533 u need a 533 motherboard... Suggestion is asus or abit if you would like to o verclock.. epox is good too if u prefer the sis controller rather than the intel..
Q2: To my knowledge no.. most other progs are similar and wil read the same thing... maybe check the bios..
Q3:your agp 2.0 compliant will work for your agp 1.0 card not to worry
Just dont try to put a agp 2.0 in a 1.0 slot..
To my belief thats really all you need... seeing as you have a ddr 2.5 i'd suggest getting one of the new asus boards that have ddr 400 support as well as agp 8x and 533 bus... Gigabyte has this too.. I fyou dont want to switch motherbopards id suggest to stick with what you have... The motherboard can be clcoked i believe to serve the 533 purpose but thats not advisable...
Hope this helps