When you feel comfortable with your level and abilities, you can head into Sen Fortress.

You can also buy the materials require to upgrade weapons from the blacksmith I previously mentioned. While this may seem to be an expensive item at first, 20000 souls in the place I have just mentioned can be gathered approximately 5 minutes. You will need to gather 20000 souls to purchase the key from the blacksmith in the Undead Parish before the bridge leading to Sen Fortress.

Of course, upgrading your weapons requires Souls right? One place that I highly recommend is beyond the Crest Gate found in Darkroot Garden.

If you find that the enemies are too difficult, suicide runs are a good method (although certainly not the best) to receive them.

Find certain items of interest and know what's guarding them.

You do not want to be fully depended on Drake Sword as it does not scale to your attributes.

Upgrade your weapons, or in your case, your Pyromancy Flame at Firelink Shrine.

There are numerous things that you can do to gain some ground once you've rung the two bells to get some advantage.

Dark souls rusty iron ring