Kraso
I have a suggestion....and I think the rest of the guys on here would agree.
The coins you have are rarer high $$ coins....to get the most out of them and to make sure you don't get ripped off I would suggest calling a few Auction Co abotu selling them
Heritage or even DLRC...
http://www.davidlawrence.com
The reason is that if you try to sell these coins most dealers aren't going to have that much to spend on one coin....and as Ricky said....it is kindof rare to find such coins and questions are going to be asked alot.
I would suggest Heritage.....they will sell the coins and take a small % out of the ended price and you get the rest....you don't have to worry if the winner doesn't get them....you don't worry about a thing.
DLRC will do the same but I think you might get better prices from Heritage.
Both of these places aren't going to rip you off.....the coins will sell for the going price....I would wait untill you could sell all of the coins at once...and not just one here and there.
Hope this helps---since you seem to want these coins I would see if your sister would let you buy them off of her....I don't like the idea of a loan...I guess it is because in Math I have been learning how much of a rip off loans are.....but be glad that you only have 1 sister....my dad is also a collector....and us kids will get the coins down the road...but I have to put up with 2 sistesr
Speedy