There’s never enough time, or not all the features can be developed, or not all things can be tested. This is good.
Embrace this limitation that seem to exist always. A small team can perform better when there are limitations. Constraints and lack of time usually can drive innovation, get new ideas flowing and force the team to adapt and focus on the problem at hand, usually getting creative results.
Get each member of the team to focus on the feature or part of the project that they are best suited to work on, have them solve the problems and report back. Then generate an overall solution based on the plan of each team member. This will force each individual to have to communicate accurately about his or her idea, and make the point clear. Focusing on less features or ideas will create a plan of action that is actually achievable.
Work with the time that was given, don’t try to change this. Focus on the things you can actually achieve and leave everything else out.