Advice on two DJ systems

I'm not a DJ but could really use your advice on two purchases...

I often host parties and my “DJ” equipment was stolen recently. This wasn’t much – just a pair of Klipsch KLF 30 speakers with a QSC GX3 amp. I currently have two Yamaha S112V speakers – but they don’t seem to do as a good with base as the old KLFs. I’m okay with the volume and sound from S112V but I think I should augment with a sub. Will need to replace the amp. And was thinking about adding a low cost, really simple mixer so I could attach a microphone for announcements, etc. This is a personal purchase.
My team has a big room in a large warehouse – this room probably covers 1/3 of a 17000 sq ft building – ballpark call it 120’ by 50’. There are many large openings to the rest of the building. This is a work/play area - it isn’t a dedicated music space – and we often have groups of 20 to 100 or that are in a part of this big room and would like to be able play music and then also occasionally do a party in the 120'x50' space. We need a lot of flexibility of where we put the speakers, amp, etc. So ease of movement (ideally rolling), setup, connecting to a computer or iphone for a playlist… is more important than sound quality. Moreover, there isn’t power to every section of this building so active speakers would be harder to setup than just stringing speaker wire from a central amp/mixer on a cart. This is a purchase I would do with the team. I was thinking about something along the same lines as the first project – two passives and a sub plus amp and simple mixer – but we’re open to alternatives.

In terms of budget, I guess I’d ideally like to keep it under $1500 (for sub, an amp for the S112s, and a simple mixer) and no more than say $2000 for the first project. For the second project ideally I’d like to do it for less than $2500 with no more than $3500.

Thanks for any advice you have on this.