^ It seems that you have missed the deadline.
See here:
http://our.upd.edu.ph/admissions.html - go to Transfer 2 (How to apply for transfer if coming from another school/university)
UP Diliman accepts transfer students from other schools every first semester only.
* Deadline for filing application for local transferees is on the last working day of April.
* Deadling for filing application for foreign applicants is on February 15.
Steps:
1. Fill out a transfer application form and pay application fee of P100 for Filipino, P150 for resident foreigner, and US $30 for non-resident foreigner, at the OUR Cashier or UP Cashier's Office near PNB.
2. Submit accomplished application form, application fee receipt, two (2) recent photos size 2"x 2", NSO Birth Certificate, and a true copy of grades (original & 3 Xerox copies) for evaluation signed by the Registrar of your school/university.
3. Foreign applicants whose medium of instruction in their previous school is NOT English should take and pass TOEFL with a score of 500 if paper-based, 173 if computer-based, or 61 if Internet-based test.
4. Follow-up of computation of GWA is around the first week of May (for local transferees) and the end of February (for foreign applicants).
5. Follow-up of results from colleges is on the 3rd week of May (for local applicants) and the end of March (for foreign applicants).
6. If accepted, get an Honorable Dismissal/Transfer Credential from your previous school (for local transferees).
7. For accepted foreign applicants, ARS-OUR will issue an Acceptance Letter needed to get a student visa for the issuance of a Study Permit from ISP.
8. Submit the following documents to ARS-OUR to get a University Admission Slip:
Honorable Dismissal/Transfer Credential
NSO Birth Certificate (original & photocopy)
Two (2) passport size photos
Student Directory ( 2 copies)
OTR from previous school (If not yet available, get a request slip for your OTR from ARS, to be given to your former school.)
9. Proceed to the UP Health Service for medical exam.
10. Submit your medical result & University Admission Slip to your college for registration.