Welcome, shungo. 
Here's one suggestion that may or may not help. Have you tried the writing course they offer at the UBC Writing Center?
WRITING 098
What level of English do I need to have for Writing 098?
Writing 098 is suitable for students who have completed Grade 11 English in a Canadian high school, students who have achieved a score of 570 or higher on the paper-based
TOEFL exam (88 or higher on the Internet-based
TOEFL),
students who have achieved a Level 3 or 4 on the LPI, and students who are currently taking credit courses at UBC.
Will I get a get a Level 5 on the LPI after I take this course?
We cannot guarantee a specific score on the LPI. It all depends on where you start, i.e. your writing ability when you start the course. Some students have a long way to go before they achieve the Level 5; for others it's a shorter journey. Certainly your writing skills will improve if you attend classes and do the work, and that will enable you to get a better score on the LPI.