Impale is a good damaging skill, but the maximum speed you can get is about 14 fps for javelins and about 18 fps for spears. For spears that is with massive IAS as well, so on a general pvp build where you want damage reduction, resistance, lifeleech and so many other things it means you won't even get that much. 18 fps is quite a lot and considering other people attack with generic speeds between 4 and 6 fps, they'll have the opportunity to hit you 3 to 5 times before you can get your attack in.
Impale is also interruptable which means that you can easily be put into stun, faster hit recovery animation or even dodge and avoid animations. That will mean you have to start your attack right from the beginning and you will virtually never get a hit to land on your opponent.
Impale is really a pvm skill and even then you have to know how to apply it.
Valkyrie is a nice skill but definately not for pvp either. People will just avoid it or use it to leech from. The only real use for it is as a distraction for fist of heavens, guided arrow, traps, thunderstorm and things like that. It's very bad when you are up against an opponent that uses rabies (since the infection spreads from the valkyrie onto you if you touch your valkyrie when she has it) and lightning fury (since it releases a lightning bolt towards you). She may get a hit once or twice here and there, but it is not something to count on unless you have a way to seriously stun your opponent. The problem is that amazons have no way to stun their opponent unless you do enough damage to take away 1/12th of their life. Even with a BotD spear I think that may pose to be difficult and the stun isn't too long so you also need luck for your valkyrie to react fast enough when that happens.
A valkyrie is not a shadow master when it comes to AI and cannot be used as effectively as a grizzly bear coupled with shockwave.
I suggest to put only 1 point in valkyrie and focus on your own damage, defense and attack rating issues instead.
I don't know if pvp spearazons will work, but if you are going to try one you had best get the dodge, avoid and evade skills which you prefer to a high level. I don't suspect that avoid will be that determinating since I hope you won't be standing still when an opponent shoots out a missile, so dodge and evade probably require the most attention. You may want to use slow missiles if you think it's not 'lame'. You are the underpowered class after all so I see no reason not to use it.
Penetrate is another skill to max out or get to a high level, because you need that attack rating bonus when you are up against high defense characters. 10000 attack rating is about the least to go for.
Since you have BotD, critical strike also requires good attention to increase your damage or you can go for low critical strike and a lot of deadly strike gear.
I guess since you've already taken up jab you're going to stick with it. A total of 115% IAS should get you to a 6.5 fps jab and a total of 155% IAS should get you to a 6fps jab attack. In itself that is not bad, but a lot of melee characters will have faster attacks.
Well.. that's what I can think of and it's not a lot. For a pvp spearazon I probably would have gone the lightning damage route, but that would have given a slower attack than jab so I guess the physical damage way should be possible or even better.