I think it is a bit of a stretch to expect to get more then 4.5 BTC for your account. If the fact that the account was sold were to somehow leak then it's positive trust would likely go away.
Plus the market for accounts is not good right now (although it is improving). If you have really received a 4.5 offer then I would suggest accepting it (especially since you indicate that you need money quickly as hero accounts tend to take a long time to sell)
I don't see how it would be able to leak that the account was sold. I have not posted any exact details on the accounts that could be misused ,such as the date of creation or the exact activity number.
I have checked this forums for previous sales and it seems that Hero accounts usually sell between 2 and 4 BTC, and some of the sales were when the BTC price was much higher. So considering the fact that the BTC is at such a low point 4.5 BTC is not realistic IMO.
Getting this kind of account with all its perks for 5 BTC is a great bargain and it is sad that some people want to take the advantage of my personal situation to try and negotiate a price well below the realistic value.