Making two drives show as one on debian?

Making two drives show as one on debian?

I rented a server from a provider and they refused to install RAID0 for me.
So I'm trying to figure out how to link these two drives so that my programs that are installed on the hd will see the space from the 2nd drive.
This is how it's setup:
df -h
Filesystem                                              Size  Used Avail Use% Mounted on
rootfs                                                  139G   93G   39G  71% /
udev                                                     10M     0   10M   0% /dev
tmpfs                                                   599M  208K  599M   1% /run
/dev/disk/by-uuid/e7a9cc0e-9caa-4d33-b60f-f1a2b4ad0ae8  139G   93G   39G  71% /
tmpfs                                                   5.0M     0  5.0M   0% /run/lock
tmpfs                                                   2.7G     0  2.7G   0% /run/shm
/dev/sda1                                               961M   36M  877M   4% /boot
/dev/sda5                                               139G   93G   39G  71% /media/hd
I did my best with my n00bness to mount the 2nd drive. Does anyone know what I need to do to make the drives show up as one?