options after youve agreed to a payment plan

I have an outstanding balance from an old credit card bill. It is almost 7 yrs old and the original debt was $5,100. I had moved out of the country for 2 years and though I did try to pay it for the first year, it proved quite difficult because of the currency difference, unreliable family members, and to be frank , my own stupidity. Slowly the balance started getting higher and higher because of overdraft charges and late fees. I endured many frustrating phone calls trying to figure out an efficient and feasible way to pay it without having to rely on anyone else to do it for me but the credit card company was not helpful and eventually I just stopped paying. I got a letter last year saying the CA was going to sue me and that the balance was now $7,200. I was scared so I called the CA and set up a payment plan. It is the only bad credit I have but it is killing my credit score. I would like to clean up my credit but I don't know how to proceed. The payment plan is barely even touching the balance so I thought if I could swing paying a decent amount with my tax returns that I could offer the CA something in return for clearing the debt. However, after reading some forums, I'm finding I may have made a huge error by doing a payment plan and cannot use the pay for delete option. So, do I have any options? Will it make any difference to my credit if I don't pay the debt in full but only settle the account? How much do you think the CA would be willing to take for this debt? Thanks everyone for any input you may have.