Try this no tools collimation web site to get you back to a rough alignment:
http://www.vvm.com/~piscescs/collimat/NoTools2.html
This should buy you some time while you read the reviews of the myriad of available tools:
Site tube
Laser
Barlowed laser <- this is what I'll be using
Cheshire
Auto collimator
etc...
(Do a Google search for "collimation tools review").