Oh congrats on reaching the third trimester, such an exciting milestone! My second pregnancy I also switched hospitals quite late and remember feeling so nervous not knowing what to expect at the new place.
From my own experience in the subsidised route, visits from around 32 weeks onward tend to be more frequent, roughly every two to three weeks initially and then every week as you get closer to 40 weeks, and not every visit will have a scan, some are just check-ups with the doctor. Charges per visit can vary depending on what is done that day, so it might be good to just ask Dr Citra's clinic directly at your first appointment next week, they are usually quite happy to walk you through the schedule and give you an estimate lah.
Hope your first appointment goes smoothly, you are almost there!