we do original material with 1 cover thrown in; 8 songs = 30 mins, so I reckon 45 mins = 10 songs plus a bit of banter; if they’re wanting 2x 45 mins* you probably need no more than 20-22 songs. Make it the simplest songs & you might be able to do it. I wouldn’t want to at that short notice.
I really would recommend slimming the setlist(s) if you can if you only have 4 weeks to practice them all – unless of course you can spend 8 hours every day between now & then…
* apparently, when Sid Vicious went solo, he’d do 2x 45 minute sets… the same 45 minutes of the same songs, played twice…