This may sound silly, but it works for a lot of the textures I create.  If you have a scanner, great, if not see if you can borrow one or the use of one.  Scan a hairy chest.  Pull that scan into your PSP or other image editor to work with it.  Then try mapping it to your character's chest.

I do a lot with book covers ... scanning them and then setting up the scans to map parametrically to book models (which I have either purchased or gotten for free on the net).

PSP is relatively cheap.  I use version 8.1, which, in my opinion was the best of the lot, and you could probably get a copy of that for dirt cheap on ebay.

However, any image editor that will let you work in layers ... that's important.  Locate the original texture for your character.  Then bring the chest hair in as a new layer.  Resize to fit and blend the hair (which can be done rather quickly using one of the layer blend modes), and you've got realistic chest hair.

Could be worse, could be raining.