No you don't need to be BCA to do MCA. Most univ. demand maths in 10+2 and 50% overall in 10+2 to sit for the entrance exam. But, it may vary according to the univ. you select.
List of some top univ. for MCA -
http://www.careerlauncher.com/colleg..._colleges.html
Not sure about the reliability of the list. You should find something similar on IMS's site too I guess.
Level of Maths will depend from Univ. to Univ. I believe.