RTR and Power Within go great with sorceries, if you don't mind doing that. If you'd rather use weapons, don't forget to throw the dragon roar on top of it all for even more power, and being rank 3 in the Path of the Dragon covenant will slightly boost the boost you get from it. Alternatively, you can stay in long enough to get the torso stone and then switch to Darkmoon for the strongest weapon buff, which can be used in conjunction with all the above.
The Leo Ring might not be all that necessary, since spears and other thrusting weapons don't do a whole lot in the first place and even a 40%-ish boost in power won't put them above the damage output of something like a Greatclub. Of course, they are much easier to hit with and they allow you to attack with a shield at the same time, so they're worth considering. Not to mention that long poking range...
Have you considered the Demon's Spear?
Rest in pieces, Manus.
Useful notes for Dark Souls 2, by yours truly: