In a 1000 pt game, you will be seriously challenged. His army will be small and compact, probably a couple of lances of knights.
His lances will be pretty small, but he can outcharge you with his longer charge range. The good thing is he probably won't take the Banner of the Lady.
You may want with a couple of blocks of infantry, prefeably one with shields, like swordsmen. The high WS of the swordsmen will make it harder for him to hit with his knights of the Realm.
Pistoliers are effective against Brettonians. The stupid prayer shouldn't effect them in close combat, since it is against shooting, and close combat is not shooting (but it could be argued that the rule applies).
I would probably go with a pegaus rider if you have one. If your blocks of troops can hold the enemy up for a turn, a timely charge could possibly break them. If I had an opportunity to charge a small Bret lance with a Pegasus rider, I would try it. The combination of 3 ST 6 attacks and 2 ST 4 attacks might even break them or tie them, taking away their charge (with some lucky dice rolls). In addition if you have a cannon, he can march block.
In a 1K game, I wouldn't take any wizards. Probably just a hero on a pegasus and your general on foot, with the Sword of Sigismund.
Rough list may look like:
General, FPA, Shield, Sword of Sigismund=110 pts
Battle Captain on Pegasus, Lance, FPA, Shield=114 pts
19 swordsmen, full command=165 pts
Detachment of Halbediers (5)=30 pts
Detchment of 5 handgunners=40 pts
19 swordsmen, full command=165 pts
Detachment of Halbediers (5)=30 pts
5 knights, musician only=123 pts
Special Choices:
6 pistoliers=114 pts
Great Cannon=100 pts
You have some marchblocking with the pegasus, pistoliers and knights. That will give you time to get a lucky cannon shot "down the throat" and take out some expensive knights.
If you haven't played against them a lot, two arguments are sure to occur. One is how many knights are hit when a cannon ball gets to them. I've always played it as whatever is hit, but only one can be hit per rank. So with a hit through the front guy and through the unit, straight down the middle you can hit 3. Others say it max at their rank bonus. In the case of a lance of 6 Bret knights, it would only be one.
The other argument is whether the pistols in close combat are effected by the Lady's prayer (if applicable). It is clear from the rules that is against shooting so you should be good to go there.
Lastly, remember that the front figure in the lance formation must see the enemy to charge them. A unit of pistoliers moving within 1" of the side of the lance, can block it up very well. They will have to maneuver around them in order to do anything.