Actually, it's a 2:1 setup since there are two lines through the load. See the following link for a more detailed explanation. Dog's right. It's not the worst setup; kind of common for the boat's vintage.
The others are right that Lewmar or Garhauser are great options. In the mean time, you could easily (i.e., cheaply) turn the rig into a 3:1 setup, gaining a 50% advantage.
1. Install a small cheek block vertically on the port & stbd side where the bitter end is now.
2. Put a shackle on either side of the double mainsheet block
3. Attach the end of the traveler control line to the new shackle
4. Run it a) to the new cheek block, then b) to the original traveler block, and then c) to the cleat.
5. I can't see how much room you have on top of the traveler, but you might be able to add another cheek block horizontally where the cleats are now. It would act as a turning block, leading the lines to the cockpit and eliminating the need to reach over the companionway.
Presto! 3:1 purchase for very little coin. The loads aren't that great and 3:1 should do the job. I did something similar to my vang. It was 3:1 (what was Sabre thinking?) and I added 2 double fiddle blocks for a 7:1 purchase.