I own a floating week 4 BR at Westgate so if I don't make a reservation then my weeks are automatically banked with Westgate. I assume for a fixed week you have to tell them if you want to use it or bank it.
They allow you to reserve a week and do whatever you want with it such as rent it or offer it to friends/family. All you have to do when reserving is provide the guest's name, address, and phone and also pay the internal exchange fee. So if you have the full 3 BR from 2011 banked you could reserve the 2BR and 1BR separately (assuming the 1 BR lockoff has the 2nd living room - if not then you may only get a studio), but you would have to pay 2 exchange fees.
You can actually reserve at any of the Westgate locations, it doesn't have to be your home resort. Everything is based on availability and there are different rules per resort/location as to what weeks are blocked for exchange or what season rules apply (compared to the week you own). The only time I don't pay an internal exchange fee is to use my unit in the current year for the first exchange. So for 2012 if I reserve a 2BR + 1BR + 1BR I get the first reservation for free and pay an exchange fee for the other 2. There may be an exception if you book multiple units the same week you only pay one fee, but I don't remember for sure. And I do believe they have started charging upgrade fees for some resorts/weeks.
Also, WG has been very good about extending weeks that have expired and letting me use them in the following year at no extra cost (just the exchange fee as usual). I believe a week is only good for 3 years, so any 2009 banked week expired in 2011, but WG has offered to extend mine for me in the past. Again, this may be due to having a floating week that expires 12/31 and it may differ for a fixed week.
I find the reservation folks to be very helpful so call and ask questions; and if they don't seem to know the answers call back later and try to get someone else who does.
If it's banked with WG I don't think you can exchange it with any exchange companies. Only your current year can be exchanged as far as I know.
If you do rent or give to friends be sure to warn them to avoid the sales meeting at all cost. My niece used one of my weeks and they told her she couldn't have access to some of the amenities (maybe the paddle boats?)until after they had their meeting. That made me very angry.
I hope this helps.
Sheila