2 answers
Hi Leah,
If it's a custom homepage component then it must be using the Visualforce behind the scene. So you have 2 options.
1) If the custom homepage component is part of the managed package - Contact the package providers
2) In the case of an unmanaged package - Ask your developer to update the code. He must be querying data based on some ordering and limiting the records.
PS: If our suggestion(s) worked, let us know by marking the answer as "Best Answer" right under the comment. This will help the rest of the community should they have a similar issue in the future.
Thanks,
Naval