For a spinnaker halyard, you could mount a "bail" on the top of the mast, afix a block to it and run an all-external halyard.
rig-rite lists masthead bails here (although who knows if they actually have them in stock)
http://www.rigrite.com/Spars/SparParts/MH_Spinnaker_bails.php
Catalina Direct has masthead bails, too (as well as spinnaker "kits" which include halyard, blocks, etc). Here are a couple of examples:
http://www.catalinadirect.com/index.cfm/product/3780/masthead-spinnaker-crane-c-34-c-36.cfm
http://www.catalinadirect.com/index.cfm/product/2702_55/spinnaker-gear-cruising-c-30.cfm
With the halyard taken care of, you're at least half way there. You could use your existing jib-halyard as a pole-lift. You'd need to figure out a pole down-haul (foreguy), and sheets and such...
But at the very least this could get you going without drilling holes in your mast.
$.02
Bruce