where is your list of genes right now?

library(gdata)
xls_file <- read.xls("myFIle.xls",sheet=1)
rownames(xls_file) <- myVectorWithGeneNames

you don't need to convert to matrix more info here on r-bloggers

I have found very useful for my novice students to use the integrated functions included in RStudio to import data that ddiez mention

This provides not only a GUI interface to import data, but also a Data preview. It will allow you to convert the data name column into row names automatically. You will be alerted if your numeric data will be converted to character or not

The newest preview version 1.0.44 can import, in addition to the classical csv and excel files, SPSS, SAS and Stata files. This is accessed from the File / Import Dataset menu file

The nice thing is that it also provide the R code to do it, so you can learn from the experience

Another option to read XLS files into R is the readxl package. If you are using the preview version of RStudio this is integrated in the GUI.

I'm assuming you know what gene corresponds to each row. If they're in order, do something like:

a <- read.table("your_table_with_values.txt", stringsAsFactors=FALSE)
b <- [this is going to depend on what format your gene names are in. 
perhaps you could read as a table and take a single column, or use scan() to read
a single line]
#all you need to do is cbind() them:
d <- cbind(b, a)

library(xlsx)
DT <- read.xlsx(file='you excel file')

you can use this package to read excel file and convert to data frame in R .