Hi,
You want to amplify frequencies 800Hz ... 8000Hz. I guess this is homework.
So
* frequencies below 800Hz need to be supressed, or in other words: higher frequencies than 800Hz need to pass --> High pass filter, HPF
* frequencies obove 8000Hz need to be supressed --> lower frequencies than 8000Hz need to pass --> Low pass filter, LPF
Do a quick search in your schoolbook how to design HPF and LPF (hardware, schematic) and how to calculate fc or part values.
Internet is also full of those informations: descriptions, explanations, online calculators, tutorials, even video tutorials.
In your schematic there are capacitors. All are involved in filter circuits, all of them are high pass filters. No low pass filter.
Thus it's no wonder that you don't get the 8000Hz thing to work. --> correct your schematic.
Remarks about the schematic:
* Don't remove part names. "The upper resistor of the two marked with 'R' " is a rather difficult description. While "R1" is easy and clear.
* add values you already know or you already have calculated, so we can check if you did it right.
* the text says "VA", but "VA" is not in your schematic. So it's not clear whether you mean V1 or VAC, VAverage, VAmplifier or anything else..
You want to know current of RLoad.
There are many "current for RLoad": IAverage, IRMS_including DC, IRMS_excluding DC, poitive peak, negative peak, peak to peak....
Since you are interested in frequency response, you need to tell the input frequency and the input waveform.
Frequency as well as waveform determines IRLoad.
Some details. (Solve the other thing first before focussing on them)
* A filter is not a ON/OFF thing. It is not: gain of 0 at 799Hz and not gain of 26 at 801Hz.
An RC filter first order will show gain of 26/sqrt(2) at fc = 800Hz.
* If you add multiple filters high pass filters in series each desinged for fc= 800Hz, then the resulting fc will be higher than 800Hz.
* If you add a 800Hz HPF, a 8000Hz LPF and a gain stage of 26, then the maximum overall gain never reaches 26, I rather guess about 23.5 close at sqrt(800Hz x 8000Hz).
**********
A real circuit needs power supply decoupling capacitors.
I recommend to add them at the simulation schematic ... just to not forget them when you build the real circuit.
Klaus