remote - Debian - move partitions to a new drive

I have a XenServer6 VM with Debian Squeeze 64bit and only 1 partition /dev/xvda1 95 GB + linux partitions:

Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1             95G   63G   28G  70% /
tmpfs                 2.0G     0  2.0G   0% /lib/init/rw
udev                  2.0G   68K  2.0G   1% /dev
tmpfs                 2.0G     0  2.0G   0% /dev/shm

I used the XenCenter to resize the available space for this VM to 300 GB. This worked. But now I need to tell the ext3 filesystem to add some space. I only found some instructions with LiveCD's etc., but my server is rental and its in a remote DataCenter, I do not really want to experiment with an remote LiveCD etc. It is a running webserver, so I need not to lose any data or partitions. I can do it at night, so there are no big troubles with reachability. The server should have a RAID (2x 1TB HDD). I have another 2 VMs on it.

The question is: how can I do it without risking too much and without LiveCD's? Is there any other way to tell the filesystem:

"look up the free space and add this to the existing /dev/xvda1 partition"

Thank you very much for your knowledge and ideas.

Caesar

EDIT: I still have free space on the XenServer main disk. I could make a new XenServer disk and add this disk as additional space to the VM. How do I then change and copy everything without downtime?

EDIT2: I've just made a new disk in XenCenter, made new partitions ext3 on it with the main partition, the ext partition (logical swap partition inside). This one is now mounted as /dev/xvdb1. Swap/EXT is not mounted (I think this is OK, aint it?). How do I now copy the whole system from original partitions to new partitions and how should I tell Debian he must now use new partitions instead of the old? I will delete the old disk (with old partitions) and this server should boot from new partition xvdb1.

Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1             95G   63G   28G  70% /
tmpfs                 2.0G     0  2.0G   0% /lib/init/rw
udev                  2.0G   84K  2.0G   1% /dev
tmpfs                 2.0G     0  2.0G   0% /dev/shm
/dev/xvdb1            184G  188M  174G   1% /mnt/xvdb1

Thank you!