Just put together as much information about your relationship as possible starting now, such as phone bills/records, email copies, letters, flight tickets, hotel bills,etc
Marriage is much easier if you do it in the UK, and you need to apply to the British Embassy in Manilla for a Fiancee Visa. If you wish to marry in the Philippines it can be costly, and a mess with the Philippine authorities, and the UK immigration, more information is elsewhere on the site and forum if you go down that route.
If you come to the UK on a Fiancee Visa you then have 6 months to marry, and must reapply before that is up for an extension, and then again after that before you get permanent leave to stay.
Nothing happens fast with the immigration, so it may be 12 months before you are in the UK, but be patient, tell the authorities 100% truth, and you'll have no problems.
