Web Master:
There's nothing for it but to give it a good strong spray of Glyphosate. Wait until its growing strongly, separate your plants from the weed with some sort of barrier, some cardboard or something like that and then spray it on ruthlessly.
If you use a fine nozzle and a protective card, then your neighbouring plants will be OK, if you are careful.
Its systemic so it'll kill off the top growth but also go down and kill the roots - which is what you need.
Check back ten days later and re-spray any bits that have survived.
Pulling it out won't help - it will only encourage it to grow more. Its like cutting hair or finger nails - the more you cut the more you stimulate new growth.