RN(註冊護士)同EN(登記護士)

You need to go back to study. To save money, check if HA or soical department offer any mature course for EN to get the RN license, which is not a degree program.
If not. then you need to save money for that. Go to OU for the Bachelor degree program for EN, you need to communicate with your ward manager.
Or if you could effort. that the way I did.
Find an university overseas, study full time in 3-4 years. (At all the school break, went back to hk to work as a private nurse --no break, work every day-- to save money for next semester). Work 20 hours during school week at nursing home at nursing assistant (with working permit).
Well.. that works for me and I got my BSN.
In fact, I did not return to Hong Kong, I was working in Australia, then I came to New York. Worked as an IC in Hospital for a few years, now I am working in an home care organization, to build the Asian program for them. Have Chinese health workshops in Chinese senior centers. Teaching our chinese seniors to live healthier..
Well.. it is a big challenge to go that far.. but sure worth~!