The attorney has suggested that I renegotiate with the seller's realtor, however, I did think that this would be something he should do. At any rate, we did get some money off of the list price, perhaps splitting the cost would be the most fair thing to do. I'll keep you all posted.
Your best bet is to get an estimate for remediation and ask the seller to credit this to you at closing. This will put the actual money in your hands to rectify the situation. Since you are unrepresented, if the seller is reluctant to work with you on this, kindly explain that if they do not go through with your recommendation they will have to disclose this to any future buyers. This statement is typically a real eye-opener for most sellers.
In New Jersey, it is most common for attorneys to act as the settlement agents, and to maintain a lead role in post inspection negotiations. Since you are not in NJ, this may not hold true for your situation.
Since you indicate you do not have a Realtor representative, I do suggest that you look to your attorney for advice and assistance in the negotiations.
Your attorney can renogiate for you if you wish. With it only being 1 point over the cutoff the seller may or may not come down on the price. Your position will depend on the price you are paying for the home. If you have gotten the sellers to come down substantially on their price they may not budge on the radon. If you have paid close to list price then you may want to stand firm on having the sellers remedy the situation. Usually, I suggest both parties get their own estimate and split it down the middle when it's this close. Also, I have had buyers take the home as is and not worry about the radon being slightly elevated but you have to be comfortable with that. Most sellers will pay for the treatment if you insist due to the fact they will have to now disclose the radon level to the next buyers. Best of Luck.