You'll probably get more interest if you don't offer a monetary prize.
You may also want to take a look at the forum threads for other GOIO competitive events to work out the level of detail and quality of presentation you should be providing in your OP.
For example right now you're still missing:
- the specific time that the event will run, kind of vital anyway, but particularly so because our community spans many timezones.
- an explanation of the structure. Your link does suggests it's double elimination, but you should probably make that clear in the OP to both clarify it and keep the information in one place.
- rules for substitutions (as a one shot tournament you can probably keep these pretty simple eg. "a player may only play for one team during the event")
- time limit rules (half an hour is considered a decent standard limit.)
- will matches be played best of one or best of three
- details about streaming; almost all GOIO events are streamed on Twitch now. You may not be capable of streaming yourself but there's a few dedicated casters in the community - if you neaten up your presentation and prove you're taking this seriously I'm sure they'd be willing to pitch in.
- details such as expected number of participants, signup process; do you need contact details from each team? etc.
fit all that into a neat, well written OP that doesn't mention money and you'll be making a much better start.
Finally, you should also keep in mind that there are already long-running competitive events that have claimed the better time slots on weekends. Therefore you'd probably be well advised to open a discussion with their organisers to see if they're willing to halt operations on the weekend you want or whether there's a better date you should reschedule to.
