Hi,
Supply us with the info Pete has asked for, and as is made clear, NEVER lie to immigration you will never get in no matter what you try in the future.
You will need a Fiancee Visa, and marry her within 6 months or she goes home, no flexibility.
Print off two forms from the UK Immigration site 9link on main page). Fill one out as a demo yourself, and send them both to her. She can then fill in the spare, and post it to the UK Embassy in Manila. ASAP.
You may be lucky and get an appointment while you are there, but she will have to go at some point to the embassy.
You both will have to prove your relationship, airline ticket stubs, letters, copies of email, SMS message bills, etc, as much as possible. Supply more than they ask, looks better. She will need to take all that to the interview.
You also need to prove you can financially support her for 2 years, as she can not work or claim off the DSS in that period.
As for airline tickets, you won't get a single cheap, they are usually 75% the cost of a return ticket. If you love her, get her back on Singapore Airlines, otherwise she'll be in a git of a mood when she lands ;D