^who told you that you need a static IP for that pupose.
MX Records map a domain name to a list of mail exchange servers (e.g MS Exchange Server) for that domain.
A Records map hostname to an IP address of the host
you might only need static IP address if above kind of services are to be hosted on your computer. otherwise the MX records, A records and any other type of records for that domain need their related hosting provider's IP addresses not yours.
for simple, if you are just owning a domain name and also registered with some other host provider. then you dont need Static IP on your personal computer.
above was some information what I thought you must know about.
any ways. for Static IP, just go to your franchise, ask them that you need a Static IP. you have to fill up an extra form with some bit of fields. sign liabilities. and pay some amount when they launched the fee was Rs.1000/year/IP. your static IP details will be given to you in 2 or 3 days.