Here's some advice from a fellow non-developer who was once your shoes 5 years ago (sans grant money) with similar revenues and skills...
Since you've managed to cobble yourself together a prototype in PHP that people will actually pay for there's a good chance you can take it to the next level, albeit slowly, with a couple books in your lap and a few long days. I suggest you challenge yourself to figure out what is the next step you need help with and figure it out yourself. Unless you are looking at some very unique problem solving chances are you can do this.
Funny story: when I started coding my web app that supports myself and my family I had never created a database or re-usable objects. I ended up with huge pages of procedural PHP code and a primitive denormalized database, because I didn't really know any better. I've managed to scale this old code across two servers, and while it's pretty horrid, making changes and troubleshooting is a breeze because it's all mine.
Thank you for the encouragement. What you wrote out here, is what I've been doing for the last year or so. I had some good friends tell me to just man up and figure out how to make what I thought would help sell my stuff. So I did. Were it not for this grant money, I'd keep on trucking along making incremental improvements to my business. Maybe in a year I'd get up to 9-10k/month. I suspect it's quite do-able.
But with this funding, there's an opportunity to do something grander while still running my little business on the side. That's new territory for me.
If you don't follow the GPs advise then contract out little pieces and do the integration yourself. No point in setting yourself up to be ripped off, you have a winning formula, be careful.
This is really inspiring. I think it's a mix of your determination to learn how to code and the line of "... The web app that supports my family". Maybe op can get someone to help them building the app with the 100k grant, but I'd certainly suggest they learn themselves too.
Since you've managed to cobble yourself together a prototype in PHP that people will actually pay for there's a good chance you can take it to the next level, albeit slowly, with a couple books in your lap and a few long days. I suggest you challenge yourself to figure out what is the next step you need help with and figure it out yourself. Unless you are looking at some very unique problem solving chances are you can do this.
Funny story: when I started coding my web app that supports myself and my family I had never created a database or re-usable objects. I ended up with huge pages of procedural PHP code and a primitive denormalized database, because I didn't really know any better. I've managed to scale this old code across two servers, and while it's pretty horrid, making changes and troubleshooting is a breeze because it's all mine.