You can do it 'all' for $1000 but IMO the results would be disappointing and there is a good chance much of that gear would end up in the classifieds next season. You could easily spend $1000, or close, just for tower speakers. Maybe you need to if wake range projection is the goal. Far less is surf range is the goal.
It would help stretch your budget by making use of any existing equipment that is satisfactory and investing in what you don't have.
You are more likely to be satisfied over the long term by either bumping up the budget or building the system one area at a time, perhaps a portion this season and a portion next season.
When you add a subwoofer it becomes almost essential that you drive the in-boat speakers with external amplification also. There are single chassis amplifiers with enough channels to run in-boats, sub and towers, but usually you end up with two amplifiers to drive so many speakers.
So you are looking at tower speakers, subwoofer, sub enclosure (as an important element) and two amplifiers. Then you have the cost of wiring, connecting cables, distribution and fusing not to mention a fair amount of misc. hardware.
Start with clarifying your objectives, such as how you would be using your tower speakers. Then set realistic expectations as to how much you can accomplish within your budget and still be satisfied for the long haul.