Find another co-founder? what is his/her role in the project?
Why losing a co-founder is a problem? Only they have the technical ability? Only they have the insight to the sector? The fund depends on their name? The fund depends on the partnership? co-founder is irreplaceable in some way? Op has time limits? Op lacks the technical/social abilities to replace partner?
HN is a good place for looking for talent, but you need to give more information about what you want to build. Also you need to create interest in people because it's really an early stage venture with low funding. Considering money is the first incentive you need luck, or you need to show that you have the chance to become a unicorn.
Also you may try angel.co.
So good luck.