Dont worry is quite normal to sruggle in wind with the 3ch verion and a 500mAh battery, but saying that I loved it and it helped improve my skills wrt flying. The 3ch version is better suited to warm summer evenings with a gentle breeze, its ideal for soaring.
It can be a bit of a jump sometimes from 3ch to 4 ch so dont be in a rush. I suggest moving the battery forward first on the 3ch version, this will give you more nose weight and improve penetration into wind, you will probably need a bit of up elevator to help it climb. Once you make enough progress into the wind, turn down wind the model will gain speed, dont let it travel to far then turn into the wind again the momentum will give you some more penetraion and hopefully you will gain a little height. Keep practicing this and soon you will get the hang of it, don't let it fly too far down wind or you will struggle to keep the plane in front of you. Once you master handling it, swap over to a 3s 700mAh and you will appreciate the difference both in power and speed.
The 4ch will definately fly better in windy conditions, but if your a novice it may be a bit tricky to master compared with a 3ch version at first, so keep those throws low to begin with. The 2s 500mAh wont be sufficient for a 4ch version either, with a lower profile on the wing and less dihedral you need more airspeed over your wings for lift.
I use a 3s 700mAh, or 800mAh right upto a 1000 mAh battery to get a decent flight times and maintain a decent flight speed. You may need to modify the battery position as the bigger batteries dont fit underneath in the pod.
I posted some pictures of my modifications with the battery on top with a canopy option on one of my posts.
I personally like flying both versions for different reasons great little planes, stick with the 3ch and get use to it. On a calm or light windy day you cant beat it.