Here's a quick one; Just post here if you think you know the answer.
Make R1 exchange routes with R2:
R1
R2
R1 config
---------
int fa0/1
ip add 204.150.10.66 255.255.255.0
ip ospf 1 area 51
R2 config
---------
int fa0/0
ip add 204.150.10.65 255.255.255.192
ip ospf 51 area 51

EDIT: The solution should be as simple as possible, and not involve change to any config already made.