Yes you can improve significantly.
I took my first full length BC exam a week before the real DAT and got less than 15 (21 out of 50 correct) and got a 21 on the real DAT. English is my second language (came to US 7 years ago) so RC was a bit hard at first. I believe having multiple good strategies is more important than your reading abilities. I didn't read scientific articles for practice at all due to time constraints and only took 4 RC practice exams. For RC section, I spent most of my time trying to figure out which RC methods worked for me and improved steadily over 4 RC exams.
Try to figure out RC strategies that work for you. BC has articles on different strategies. Good luck!