adding caption to pictures

hya im trying to add caption to pictures i.e 1,2,3,4 but on site it displays as -1 , -2 , -3 , -4. is there anyway to get rid of the line. also i have tried adding a (add to shopping cart ) short code in the caption area of the picture using wp Simple PayPal Shopping Cart. this works for the first image but if i add it to the others they start to disappear. any help would be much appreceiated or any alternative to getting the shopping cart to display images side by side the site is currently http://tbclothing.gioroo.com/ the page that shows this is http://tbclothing.gioroo.com/mens-dg-jeans/