Upgrading acoustic guitar vs upgrading an amp

I currently have an acoustic (Alvarez RD20SC) and an electric (Squire Standard Strat) but am currently only using my acoustic for Sunday worship. I currently am using a keyboard/pa amp (Kustom KMA 65) with a digitech RP100 processor for the electric and a Zoom 504 II processor for the acoustic. I have been thinking about selling my electric and amp to either get a better acoustic (something in the $400-600 range) or get a good acoustic amp like an Acoustasonic, Genz Benz Jr, or an ultrasound. I have heard some people here say that an amp can make a huge difference with a budget electric. I was wondering if the same would be true when using an acoustic with a bridge pickup. If I get a better guitar will I be able to tell the difference after the sound is translated by the pickup and the amp? Would I hear more of a difference with a better pickup?