I'm working as a temp staff at my company there for quite some
time already but the thing is those perm staff ostracize
temp staff like us.
One obvious example is, a colleague is sending out invitations
to everyone in our team including the newly recruited perm staff,
except me because I'm the only temp staff there. -.-

It will take a while before they accept you.
If there's that particular person who ostracize you.
Than why not work around other perm staff members?
Perhaps they are better colleagues just that you didn't get the
chance to talk to them.
I previously was also left alone in the office since my job
scope has got no relations with other departments just that they
will come and use my computer for printing purposes.
So shld there be any chance of you getting to talk to them.
Than you should make the first move if you want to have a easier
life out there.
Since you're a lady, than if the other colleagues are ladies in
their "auntie's" age range, than beware of how you dress to
office.
You don't wanna see the ladies having sour grapes do you, than
you'll get a tough time iniside.
one way is to ask them out for lunch or often go to the pantry
when there's 1/2 person there.
Find a chance to talk to them.
Or during lunch time, when majority of the people are out, there
will be either 1/2 person left in the office, so you can talk to
them asking abt their lunch etc as your opening speech.