Unfortunately in won't lift any restrictions or limits with regards to private messaging. So the other way must be to naturally rank up your account even though it will take a while. Keep in mind that newbies messaging to another member they will be reminded with this message:
!!! WARNING: This user is a newbie. If you are expecting a message from a more veteran member, then this is an imposter !!!
So even if you are a Copper Member users will still be warned about you being a newbie member in the forum.