Hi!
The whole of the A-Level is out of 400 (200 UMS for both the AS and A2)
The coursework grade you've been given is the raw mark, not the UMS, as the coursework is converted into 80 UMS.
Let's assume that your coursework is just an A, so would be 64 UMS.
To get an A you would need 80% of 400 UMS, which is 320. At the moment you have a total of about (depending on the grade boundaries for coursework) 235 UMS. To get an A you would need 85 UMS in Unit 3 (out of 120), which is just over a B (84 UMS is a B).
Assuming you are doing Option E, a B has been 44 and 42 out of 70 for the past two years.
Hope this helps, but remember that this calculation is dependent on what the coursework's grade boundaries are, one or two raw marks can have a big impact on the UMS mark.
Good Luck! I'm doing this option as well, and have been neglecting it recently