does any one know waht is the purpose of choosing candidates and party through two ballot papers???

Why we need two ballot papers?? hmm.. well if my knowledge is correct, we are adopting mixed election system which means we will have two different election system i.e. first-past-to-post (FTFP) one and proportionate one. So we need two ballots.
Second, if the party wins in proportionate system but its candidate loose, then i am afraid, nth can be done. The party will choose its new member from its closed list of candidates for proportionate system. for eg: Girija's name is in proportionate system and Sujata Koirala is running in FTFP. If Sujata loses, she loses. But if Congress wins then it will pick Girija from its list. Hope it clears up....
We need to select our best candidate and also, the party which can implements the policy and plans we hope for....