Since you mention that you have achieved "amazing results", I am assuming that you have some sort of a prototype to show to an angel/seed investor. Also, the fact that you managed to get a government grant (which I assume you didn't have to give up any equity for) is a good thing and shows creativity on your part.

That along with a well-crafted pitch about your vision for the product and the reality of the specific problem you are trying to solve might be good enough to start having conversations with some angel/seed investors. Assuming you get some initial commitments, you could then open up a public funding solicitation on AngelList. Please do consult your corporate lawyer for specific do's and don'ts of process of public solicitation.

Also, you can try to limit the portion of this $500K going towards founders' salaries by keeping those at a bare minimum.

Finally, you'll also need to think carefully about the amount you want to raise. Will this $500K be enough to take you to your series A?

Happy to brainstorm more or provide feedback on your pitch deck.