Yes I do build strings for other people. You are right, you have the pegs as apposed to the anchors. If you can use a string to get the measurements I cab build you a set. The main number i will need is from the post on the bottome cam to the center of your nock point. This allows me to center up your center serving so the string moves more evenly. The rest of the numbers I can probably get from my friends at Martin since I have the specs on your bow.
My normal price for a set of strings is $50 US. I normally include shipping inside the US so I can probably do you a set for $55 US shipped.
As for upgrading, if you are going to be target shooting you may not want to bother. Some of the older bows are the best shooting for paper punching.