Should I buy a power amp.

I thought going w the Anthem i was getting high quality, although I understand the mrx 540 isnt as good as the avm 70 or 90. I honestly wish I would have waited and got a processor and separates. 

In your situation as your speakers are easy to drive and you’re enjoying the sound I would not recommend adding an amp.  As mentioned, you’d still be stuck using the preamp section of an AVR, which will continue to be a big bottleneck to significantly better 2-channel performance.  For better stereo in the longer term you’ll want to focus on adding a good stereo integrated amp or separate amp/pre (via the Anthem’s preamp outputs) that’ll allow you to completely remove the AVR from the 2-channel signal path, which is ultimately what you want.  And then upgrading your speakers, source, and cables would make further significant improvements.  The good news is you can do this in incremental steps and get huge improvements along the way, so keep reading/learning, go out and hear as much equipment as possible (going to AXPONA is highly recommended especially if you’re new to this and have limited access to good dealers), and enjoy the process!  
As for HT, you’ve got a good AVR that should serve you well for a long time, and adding a center speaker can help especially if people will be sitting off center.  If not and it’s just you in the sweet spot, with your equipment and proper speaker placement you should be able to get a good phantom center image so if you’re happy with that as is you might be able to skip a center speaker and put those funds toward better 2-channel performance.  Hope this helps, and best of luck. 

Hey man can we chat on the phone. I th8nk i understand what your saying but idk. I got a little confused. Im very interested in what you said though. Tha k you for your help

Sure, be glad to.  I think if you click on my name you can DM me and we can go from there.

I’m not sure which way you should go but I have some advice on the center channel. 

If you sit in 1 place in the middle the center doesn’t add much.  I know this from a lot of experimenting and professional experience.  It’s real value is when you sit off-center. 

Further, if you get a center a 3-way is usually much better than a 2-way, with horn loaded centers a possible exception due to low cross point. 

My experience is you are better off with rear surrounds than a center in terms of movie experience. 

Also, one annoyance of the modern Anthem line is they follow the Dolby specs too tightly.  Netflix for instance has a lot of Dolby Surround encoded content, which should have Surround and center, encoded as Dolby Digital 2.0.  Anthem MRX will ONLY play this back as 2 channel, turning off your center and surround speakers under any and all settings. 

Other brands, and prior Anthem processors, allowed you to apply Dolby Surround, or other matrix processing to 2.0 sources.  Not Anthem. It will do it for PCM and Amazon for whatever reason doesn’t do this.  

Note that the processor will say "Dolby Surround" even though it’s clearly NOT being applied.  It’s a significant bug that it displays this when its’ not on. 

This is how I know what the center channel does/does not do.  I was being double blind tested by Netflix!! :D  Sitting in my favorite couch position, I could not tell the center was not the source of dialogue at all.  At all, and I consider myself a pretty good listener.  Of course, it's easy to tell surrounds are not working but unless you know the source movie you don't know if they SHOULD be on.  It was listening while lying down elsewhere that I discovered this issue.