No I don't think that you are being ripped off...you said that your SIL paid $1500 with using frequent flyer miles...I think that you prob got a better deal bc think about it, there is only a $300 difference, assuming it is the same amount of people for the same amount of time. The miles that they used were prob worth more than $300.00. In today's day and age people feel pre-historic using a travel agent, they feel like they can save a buck by searching on the internet, some will find cheaper prices, some will not. I wouldn't stress it. Since you have so much time before you leave, i would watch the prices, the day you see it go down, contact your travel agent and tell them that you would like for them to honor the new price. Most will do it, as long as it is 90 days prior to travel.