symbols for ep3c5e144 and ep3c25e144 in Eagle
You can find Cyclone III documentation on this page.

In device handbook, look for "Table 1-2" (p.16). This table shows all available vertical migration options for Cyclone III family. "Vertical migration" means that when you design your board for one particular FPGA, you can replace this fpga with a higher density one (which has all the same pin layout etc.).

According to this table for E144 package EP3C5 and EP3C25 are compatible so you can use device symbol for EP3C5 instead of EP3C25.