$3000 isn't nearly enough for me (4 folks in school and feeding 5 - ugh) plus I've always hated the idea of having to go to Colonia for my money every month, so I wasn't thinking too much in terms of WU as a primary means. But yeah, it's doable and it's not a bad option overall.
I send money to my wife's relatives all the time via Western Union in Paraguay. I sent once in USD and they had no problems receiving the transfer in USD that one time. All the rest of the times I've sent in Guarani so they didn't have to deal with changing the money themselves (WU actually gives better rates than the cambios where they live, in the sticks). In fact, I just sent some Sunday.
Considering that you can get Dollars out of ATMs in Paraguay, like Uruguay, I'd think you should be able to get dollars no problem in Uruguay at WU.
I think the $5 fee is for the longest time to pickup (3-5 business days I think it is), whereas it costs $8-10 to do it for immediate pickup. Also, as I just found out today when my girls went to pick up the monetary "care' package (my Sunday sending), if they tell you that you can pick up the money on X day, plan the following day, unless you specifically received an email saying that it was now ready (they send you an email when you first send the money that has the day you can pick it up, then they will sometimes send an email if the money gets there earlier).
When I sent the money on Sunday I got an email telling me it would be available in Paraguay for Friday. The money left my account on Monday, so I assumed everything would be alright (as it usually is). The girls went to pick it up today and were told the transaction was non-existent. Upon calling WU, I was told the money would not be available until 7:48 PM Eastern time, which would be a bit late for them there in Paraguay (the place closes at 6:00 pm and it wold be nearly 11:00 PM until it was ready. Not what I call being ready for pickup on Friday, which is a pisser considering they already had my money. The delay is supposedly because of ACH clearing times, but when it's cleared, they have it.). Nothing they could do about it, they told me.
I always send via the ACH option. I usually get the second email telling me money is ready early on the following day and was not expecting this kind of problem. Poor girls had to ride a motorcycle 50 kilometers to get to the nearest WU. But hey, it happens.
It's been a long time since I first set my account up (2006), but I think you have to verify your checking account before being able to use it. Otherwise you can use credit cards and debit cards, but I think those are the immediate pickup for $8-10 services.
Their website sucks at times. I've seen it go through evolutions from just horrible to only really bad errors every once in awhile.
Don't ever send from here, BTW (not that you would, just for anyone else who's reading). It costs on the order of 20-30%!! No way Dollars. And of course, a fairly low limit.