There is no such thing as "bottlenecking"
If, by that, you mean that upgrading a cpu or graphics card can
somehow lower your performance or FPS.
A better term might be limiting factor.
That is where adding more cpu or gpu becomes increasingly
less effective.
You buy a APU for the excellent integrated graphics.
But, there are no real good CPU upgrades, particularly for a gamer.
If you install a superior discrete graphics card, you will have thrown away the big advantage of the APU.
Then, you are left with a relatively weak cpu. Most games depend on only a few fast cores.
Bottom line.....
What you get with a APU is what you will live with forever.
Your A10 is slow in single thread performance which is what most games need.
To assess the possible benefit of a GTX980 card, run this test:
Run YOUR games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.
Modern processors are all about DDR4 ram.
If you want to keep your DDR3 ram(worth perhaps $80 on ebay, then the strongest platform will be lga1150 based and a intel processor.
Look up the passmark ratings for candidate processors.
For example, your 4 thread A10-7800 has a rating of 5017 and a single thread rating of 1537.
The single thread rating is most important for games.
The 4 thread i5-4670 has a rating of 7413 and a single thread rating of 2153.
All that said, consider selling your old parts and look for a more modern 8th gen lga1151 based platform.
The entry level $130 8th gen I3-8100 has a rating of 8105/2100.