Show name of dataset in graph

Hi,

I?ve written a script to run several multivariate statistical analysis
automatically.
As one result a biplot and screeplot is produced.
Now I?d like to display the name of the inputdatset as part of the title of
these graphics and I do not want to enter it each time I run the script.
How can I extract the name of a dataset?
An (shortened) extraction from the script:

Test1 <- function(pri, sec, Pca, Ca, Dca){
#pri  - primary Parameters (biological Dataset (abundances))
#sec ? secondary Parameters 
#Pca, Ca, Dca ? Default=F, If set to TRUE these Methods are active

several mathematical Operations

biplot(pri, pc.biplot=T, main=paste(?PCA - ?, ???)

.

Instead of the ??? I? d like to have a variable.
For example if 
Test1(dataset.typ5, sec.typ5, Pca=TRUE)
then the title of the plots should be 
?PCA ? dataset.typ5?

Does anyone know a way?

Regards,
oli