Hi there Janice Mae, welcome here to the forum.
FLR (M) Further Leave to Remain
The costs are £550 for postal applications or £850 for the premium service at one of our Public Enquiry Offices.
You need to book an appointment if you want personal application at UKBA Office (PEO)
Whether to do this or not is really down to budget.
Personally, I would say if you can manage the additional cost it's well worth it as it does save a lot of waiting under stress, as you will be given the FLR on the same day.
FLR(M) Paper form is here:-
http://www.ukba.homeoffice.gov.uk/si...lrm1020091.pdf
FLR guidance notes here:-
http://www.ind.homeoffice.gov.uk/sit...lrm1020091.pdf
Look to section 11 (Documents) to review what needs to be supplied.
Please take a look at the links. If you have any questions about the requirements just fire away here, everyone is generous with their experience and support.
Try not to get too worried. To be honest it's basically a formality and you should have no problems at all. Better to apply sooner rather than later.