This is one possible solution.
You can shrink one or more datafiles from the PROD tablespace. For example
alter database db datafile '/oracle/oradata/prod01.dbf
If there is more than 50m being used the statement will return an error.
If you have dbastudio running, you can see the amount of free space in each file and this will make you job easier.
After you have enough space, you can extend one of the files in the PRDTST tablespace. Suppose it is currently prdtst01.dbf is currently 50m
datafile '/oracle/oradata/prdtst01.dbf resize 150m;
OCP DBA 8i, 9i, 10g