best recommended procedure?

Hi all,

I have this situation,

We are using an open source application which is publishing its
Subversion repository on the internet through http, and they are
committing changes every day. I *don't* have commit privileges over that
tree.
Ti fit our needs, I have many files tweaked and many others added to
that project.
Every time I download the latest version I need some -a lot of- time
manually re-plugging my changes to that project.

I have a Subversion installed in a Linux box and I use xp,

My question is,
Which would be the best way to create a branch from that project,
considering that I can only read that repository?

Would check out that repo and store it locally work? svn will not see
remote changes on their server,
Will then checking out that project daily work? svn will not keep track
of the paired main/branch since the main is happening in a different
servers.

Can Subversion create a branch in my local server that is bonded to the
trunk in theirs?
if so, can someone point me in the right direction,
if not, I will appreciate to hear any recommendation.

Many thanks in advance.

-- 
Andres Paglayan
andres@paglayan.com
Ph: (505) 986-1561
Santa Fe, NM USA
Open Source is like Love. The more you share it the better it gets.