@sunil.......dont think of getting married before getting rid of your first wife. you will land in a lot of trouble. on what grounds do you wish to apply for divorce. there should be solid grounds to apply for divorce.
is your wife with you or has she gone away? if she has gone away. start depositing some money regularly in her bank account through cheque. dont let her know about this, every month deposit some money.. this will help you in your maintainence cases later which she might file on you. you can prove her case false by doing this.
regarding allegations of dowry harrassment, write an application to the nearest police station in writing, intimating them about the threats being received by you. this will save you in future. if you are living with your parents. move out of that place and stay at a rented place so that parents are not pulled into this mess.
find a lower paying job for the time being. this will help you in your maintainence case.
you cannot prevent a 498 case, remember that, but you can take precautions. ..all the best