Rio Haryanto says he and his management team will hold meetings in the next couple of weeks to try to ensure he can complete the Formula 1 season with Manor.
The Indonesian signed at the start of the year but only had enough funding to carry him through to the conclusion of the Hungarian Grand Prix.
He secured a deal to race in Germany and now has four weeks before the next race in Belgium to find the investment required for the final nine races of the season.
Should that not happen, it is believed Mercedes junior and Renault reserve Esteban Ocon is in the running to take over the seat following the summer break alongside Pascal Wehrlein.
"It will be quite a busy summer break for me," said Haryanto.
"We need to find some financial support from some sponsors.
"My management are currently working very hard, we're going to have a few meetings over the next couple of weeks and hopefully there is good news coming out of it.
"I'm disappointed. It's not easy as there is still a doubt as to what is going to happen in the future.
"I believe in my management and they are currently working hard to secure the seat for the whole season."
The Indonesian government has backed Haryanto's foray into F1, with funding coming from state oil company Pertamina, and talks ongoing to release more money.
When asked if he would be frustrated if he did not get to finish the season, rookie Haryanto, whose best finish is 15th in Monaco, said: "Yes, because my aim was always to finish the season.
"I would be disappointed if I can't race the whole season."