More volts

I have an 87 runner 22re. I need more voltage or something, my lights dim at idle and my rear window struggles unless I give a lil gas and get the alternator goin. can I get a higher voltage battery, and if so what voltage should I get? or should I get a high output alternator?

 

I would start by checking wiring connections, then take the alternator and battery to get it tested. If the alternator is not the issue, getting a bigger alternator will not solve your current issue.

edit to add: You don't have a shitload of accessories do you? (Aftermarket Lights, Winches, Subwoofers, Amps)

 

The headlights are higher power, not a ton but more than stock, all connections are good. I just noticed your accessories comment. The headlights and amp with subs :/ I'm getting a capacitor to try and help out with powering the amp and subs.
I had the alternator tested a few months back and it was good and the battery is 2 months old. should i test the alternator again?