DB links are probably not going to work as a solution. Oracle7 is crazy old.
The question's facts are little limited. What types of objects (e.g., tables, stored procs, triggers, etc.) are involved? How much data? That said:
As it relates to table data, my solution would be to spool the data to text and access the text via external tables you setup in the 11g db.
In the 11g db, create the tables with the structure and referential integrity you require. It's been so long since I used Oracle7, so I don't think you can leverage DBMS_METADATA to obtain this DDL. You may have to get creative to reconstruct it.
Fill them with data as selects from the external tables.
Finally, index the new tables as desired.