Hi - I am not sure if you are saying that your LMIA will expire in 3 weeks, or it has already expired 3 weeks ago - please clarify!
Since you are on a PGWP and your current job is not LMIA-confirmed, the 600 point bonus requires 2 things:
1) a valid LMIA to supports a permanent resident application
2) a written offer of permanent, full-time, non-seasonal employment upon obtaining permanent resident status.
If you have those things and you are eligible to apply to FSW or CEC, submit your EE profile ASAP. you will get an ITA at the next draw.
If your employer obtained the free LMIA to support a PR application, you cannot use it to obtain a new work permit. If your employer paid the $1000 fee to support the PR application AND a new work permit, you will have to apply for the work permit before the LMIA expires. Not sure why you would want to do that, though, since you still have another year on your PGWP.